UN Secretary-General Ban Ki-moon urged Philippine typhoon survivors Saturday to "never despair", vowing to rally global backing as they rebuild their lives from one of their country's deadliest disasters.

"Never despair. The UN is behind you. The world is behind you," the UN chief said during a visit to the devastated central city of Tacloban, which suffered more than 5,000 deaths from Super Typhoon Haiyan as it crashed through the central islands of the Philippines on November 8.

Wearing a baseball cap and a tan shirt, the 69-year-old South Korean UN chief walked through a narrow, debris-strewn street in Fatima, a coastal district in the city of 220,000 people that was obliterated by tsunami-like storm surges wrought by the typhoon.

A ship that ploughed through the neighbourhood after being hurled by huge waves lay stranded nearby, six weeks after the deluge.

Ban also visited a Tacloban tent school, put up by the UN Children's Fund (UNICEF), where pupils who had lost their homes sang Christmas carols for him. He handed out backpacks to almost 200 elementary school children there.

The typhoon, one of the strongest ever to hit land, left 6,102 people dead and 1,779 others missing, according to a government tally.

Ravaging an area the size of Portugal, it inflicted $12.9 billion in damage and left 4.4 million people homeless. The Philippine government said it would need $8.17 billion over four years in a massive rebuilding effort.

The UN earlier this month launched a global $791-million call for aid to take care of the needs of the survivors over the next 12 months.

"This is a tragedy, but it can be overcome when we are united. I am here to bring that unity and solidarity," Ban told reporters, speaking beside the grounded ship in the midst of the ruined Tacloban neighbourhood.

He said he was "very impressed" with the efforts of the residents, many of them forced to live in crowded evacuation camps and makeshift tents, to get back on their feet.

"The people of Tacloban are a very resilient people and are returning to their normal lives," he added.

Ban arrived in the Philippine capital Manila late Friday for a three-day visit and called on President Benigno Aquino earlier Saturday before flying to Tacloban.

"President Aquino thanked Mr. Ban for the United Nations' support for our relief and rehabilitation efforts," Aquino spokeswoman Abigail Valte said on government radio.

"The president also thanked Mr. Ban for the visit, for showing concern for our people," she added.