The Philippines, which suffered the wrath of the most powerful storm ever to hit land in 2013, could complete its rebuilding in as little as two years, a UN official said on Tuesday.

Areas ravaged by Super Typhoon Haiyan had shown dramatic improvement since the disaster barely two years ago, said Margareta Wahlstrom, United Nations special representative on disaster risk reduction.

Wahlstrom made the remarks after a visit to the central island of Leyte which suffered the brunt of Haiyan which devastated an area the size of Portugal and left at least 7,350 people dead or missing in November 2013.

"It was encouraging to see how much progress they have had in two years," she told reporters on the sidelines of forum on disaster relief.

She said that usually, when major disasters strike, it takes up to 10 years for the affected area to fully recover.

However Leyte was reviving quite quickly with a lot of investment and construction going on and the agricultural sector making "huge progress".

"We don't need to think about 10 years. We can think about two years," she said.

"If you go there now, you will already see important change. If you go there in another two years and it (the recovery) continues at the same pace as of now, it will be very visibly a new place," Wahlstrom said.

She credited local towns for diversifying their economies and for efforts to rebuild their infrastructure.

Whole towns were destroyed by Haiyan with the government forced to provide survivors with temporary shelters which were criticised for being unsafe and poorly built.

But Wahlstrom said she had seen a lot of permanent housing being constructed with many people ready to move in.

The Philippines is one of the world's most disaster-prone countries, at risk from earthquakes, volcanic eruptions and an average 20 typhoons yearly.