Portugal has declared a day of national mourning to mark the deaths of seven who died in wildfires that have burned through the country's west coast.

More than 100 wildfires are stretching thousands of firefighters to the limit in northern Portugal. The country’s worst spate of fires in recent years is blamed for seven deaths since they spread out of control over the weekend.

For people have died so far in wildfires raging in central and northern Portugal and over 40 have been injured, state news agency Lusa reported on Tuesday, as authorities evacuated more villages overnight.