Facing an unprecedented drought, Portugal's government recommended 43 municipalities temporarily increase water prices for their biggest consumers and suspend street-cleaning and watering in public parks and gardens.

All of mainland Portugal is suffering severe or extreme drought following heatwaves over recent months, the national meteorology institute IPMA says.

Environment Minister Duarte Cordeiro said late on Wednesday that, out of the 61 dams in mainland Portugal, 10 are in a critical situation, with the stored volume of water below 20% of their capacity.

The nearly dry dams supply 40 municipalities in the north and centre of the country and three are in the tourism-dependent Algarve.

Although the country as a whole has enough water in its reservoirs for two years of consumption, the 10 in a critical situation do not have enough for one year, Cordeiro said.

Portugal has a total of 278 municipalities and they are responsible for providing water to the population.

In the 43 worst affected, Cordeiro said the government recommended that for the period when the drought was most severe, they should increase the price for families and companies that consume more than 15 cubic metres of water per month. The country's average family consumes 10 cubic metres per month.

They must also "temporarily suspend non-essential uses of water, namely for washing streets and watering green spaces, and in decorative fountains and swimming pools," he said, adding the government would help to ensure the rapid implementation of these measures.

"There is always the legal possibility for the government to adopt measures with more force than recommendations, though it is not necessary for now," he said, saying the municipalities were willing to act.

In February, the government ordered six dams to halt electricity production and, as of August, Portugal cut irrigation of golf courses and public parks and gardens in Algarve to avoid having to ration water for human use.

(By Sergio Goncalves; Editing by Inti Landauro and Barbara Lewis)