Dutch authorities will reactivate the National Heat Plan Saturday as temperatures are forecast to rise above 30C (86F) across much of the country, public broadcaster NOS reported on Friday.

The measure will apply to the provinces of Zeeland, South Holland, North Brabant, Limburg, Utrecht, Gelderland and Overijssel following forecasts of prolonged hot weather.

According to the Royal Netherlands Meteorological Institute (KNMI), temperatures are expected to reach around 29C (84F) over the weekend before climbing to as high as 32C (90F) early next week.

The weather agency also warned that the ultraviolet (UV) index will be very high, increasing the risk of sunburn for people without adequate protection.

The national heat plan is activated during periods of sustained high temperatures to alert healthcare providers, informal caregivers and the public to the increased health risks posed by heat, particularly for vulnerable groups such as older adults, young children and people with chronic illnesses.

Health officials said older people are especially at risk because they have a reduced ability to regulate body temperature and may experience a diminished sense of thirst, increasing the likelihood of dehydration.

The National Institute for Public Health and the Environment advised residents to drink plenty of water, keep themselves and their homes cool, and watch for signs of heat-related illness, including headaches, dizziness, fatigue and excessive thirst.

The Netherlands previously activated the national heat plan from June 18 to June 29 during an earlier spell of extreme heat.

It marks the second activation of the plan this summer, matching last year's total. (AA)