Deadly wildfires in central and northern Portugal have pushed emergency services to the limit and much-needed reinforcements will arrive on Wednesday from Spain and Morocco, the civil protection authority said.

A state of calamity has been declared in Portugal after 100 wildfires left seven dead and endangered 210,000 people.

More than 100 wildfires stretched thousands of firefighters to the limit in northern Portugal on Wednesday, with seven deaths since the worst spate of fires in recent years spread out of control over the weekend.

Thousands of firefighters continued their efforts to extinguish over 100 wildfires in northern Portugal on Wednesday.

Three Portuguese firefighters died on Tuesday in one of dozens of forest blazes ravaging the country's central and northern regions, bringing the death toll from the latest wildfires to seven people since Saturday,

Portuguese national police said that they have arrested seven men suspected of having started wildfires in recent days. Authorities have prohibited the use of heavy farming equipment to reduce the risk of inadvertently starting a blaze.