Tropical Storm Noul pounded Vietnam on Friday, killing one person and injuring dozens more as it unleashed heavy rains and high winds on the country's central coastal region, authorities said.

Images on state-run Vietnam Television showed damaged houses and trees, and power poles pulled from the ground as the country's biggest storm of the year made landfall in Hue, Vietnam's old imperial capital.

On Thursday, authorities said more than one million people across three central provinces as well as the city of Danang would be evacuated.

At least one person was killed and dozens others injured, state media reported, as 90 kilometre-per-hour (56 mph) winds struck.

"It was scary as the wind was so strong when the storm arrived," said Nguyen Xuan Vu, who lives in Hue. "So many trees are down. Our city looks in bad shape," Vu told AFP.

Late Friday, the storm was downgraded to a tropical depression, according to Vietnamese forecasters. All airports in central Vietnam remain closed while a ban on fishing vessels has been in place since Thursday.

Electricity has been completely cut off in Thua Thien Hue province. Vietnam is routinely hit by tropical storms from around May to October, with its central coast most frequently affected. Official reports said 68 people have been reported dead or missing in national disasters this year.