Some UK-Australian dual citizens say they have begun the process of renouncing their UK citizenship amid the fallout from new passport entry rules.

From February 25, citizens of the UK will be required to enter that country using a valid British or Irish passport or a certificate of entitlement (COE), including those who are citizens by birth through a UK- or Irish-born parent.

If they do not have either, they will need to face two costly options — renewing their passport or renouncing their citizenship.

From February 25, dual citizens of the UK and Ireland will be required to enter the UK using a valid British or Irish passport, a change causing major headaches for dual citizens with imminent travel plans.

ABC has been contacted by hundreds of readers who say they are frustrated and confused by the sudden change.

A Department of Foreign Affairs and Trade spokesperson confirmed officials had relayed concerns from British-Australian dual citizens to the British High Commission in Australia.

While renewing the British passport may be cheaper, it is not an option for some who do not have the correct documentation.

Others have weighed up the option and say they do not see the point or benefit of holding both nationalities anymore.

Mike O'Connor, who has held Australian citizenship and an Australian passport since 2007, said he believed renouncing his citizenship was the best option.

"It made the most sense because for me, the UK passport was an irrelevance," he said.

"The British passport has become something that's actively a hindrance and something I would have to upkeep."

Mr O'Connor's mother, who lives in his hometown of Sheffield, England, is unwell and he said he needed to be ready to travel to England with ease.

"It's just a matter of time before the call comes to attend a funeral and the irony is my partner is Brazilian and we would travel there together," he said.

"He would breeze through with an ETA on his Brazilian passport and I'd arrive to all this bureaucratic nonsense."

'Ditch the thing'

Mr O'Connor has begun the process of renunciation by sending the relevant documents to London.

It will cost just under $1,000 to renounce citizenship.

A new British passport costs less, at about $190, and a Certificate of Entitlement costs $1,100.

"It's prohibitively expensive, but I thought, 'No, I'm going to do it,'" he said.

"It's a bit of an emotional thing for me because I feel like I have been betrayed by this [thing] I never signed up for.

"First it was Brexit, so the UK passport lost the ability of more ease of travel, and this happened the other day, and I thought, better to ditch the thing."

Your guide to new UK passport rules for dual citizens and general entry changes beginning in February.

Lynda McDowell was born in Australia in 1965 and lived here for three years before her parents moved her back to the UK and she was brought up in Scotland.

She emigrated to Australia in the nineties and has not had a British passport since 1995.

"I've always travelled on my Australian passport and don't consider myself British," she said.

"I don't see what benefit it is to have two passports and there's a risk to travelling with two documents as well. I think it's totally unfair."

Ms McDowell said it was a personal choice but believes others will follow suit.

This week, she sent the forms off to renounce her British citizenship, a process which could take up to six months.

"We were meant to go to the UK end of April, so we're sort of sitting in a no-man's-land, but I just can't travel to the UK until that's done."

The British passport is seen as "irrelevant" to some Australian dual citizens after Brexit. (UK Government/Reuters)

Ms McDowell said it was her only choice as she did not have the appropriate documents for the British passport and did not want to get a certificate of entitlement for a similar price.

"For me, British citizenship is now meaningless and it's not a lifestyle I would want to adopt and I'm just going to renounce it," she said.

Ms McDowell said the application was still cheaper than a certificate of entitlement (COE).

"I always saw my dual citizenship as something that sat in the background. I never thought this would come up," she said.

The UK government described the changes to the passport rules as a "significant step towards digitising the immigration system and paves the way for a contactless UK border in the future".

According to the British Home Office website, you can apply to give up (renounce) your British citizenship or status.

If accepted, you'll get a "declaration of renunciation" that you can use to show that you're no longer British.

As part of your application, you may need to provide supporting documentation such as your birth certificate, evidence of your nationality, evidence of your parent's nationality and evidence you will maintain another nationality if you give up your British one.

For those dual citizens who do not wish to renew their passport, there are barriers and confusion surrounding renunciation.

Gerry Prewett, who was born in the UK in 1953 and migrated to Australia in 1990, would be happy to renounce his UK citizenship but is unsure what that would mean for his UK state pension.

"When we were going back to the UK, I realised there was no real advantage to having a British passport because my wife doesn't have one, so I didn't bother renewing it any longer," he said.

The 73-year-old migrated when he was 37 and is worried he might not be able to access money he had earned for his pension up until the time he left.

The UK State Pension is a government-funded regular payment for retirement, based on your National Insurance (NI) contributions, providing a foundation income from the state pension age of 66 years old.

He says once he gets clarity on the payment, there will be no other reason to remain a dual citizen.

"The passport did nothing for me and it was just a cost," he said.

Renouncing not an appropriate choice for all

As of 2023, the ABS recorded 1.1 million UK-born people living in Australia.

But the choice to renounce dual citizenship may not be appropriate for everyone.

ANU associate professor and citizenship expert Danielle Ireland-Piper said she did not believe there would be a broad trend of renunciations by British citizens just yet.

"I'm not convinced we will see an increase in people renouncing their British passports because there is still a convenience to having one, and you know this captures Irish passports too, where we've actually seen applications for their passports go up after Brexit," she said.

And for others, it may not be appropriate as the UK Home Office says people's right to live and work in the UK — and their children's — will be affected if they give up citizenship.

They will also lose their right to vote. (ABC News)

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