Bodies are still being found under the wreckage almost four months after Super Typhoon Haiyan ravaged the Philippines as survivors struggle to rebuild their lives, officials said Thursday.

The government's confirmed death toll of 6,201 has not been updated for a month, as officials investigate whether the recently-discovered corpses are among the 1,785 listed as missing.

UN undersecretary-general for humanitarian affairs Valerie Amos recounted the shock of discovering the dead during a visit Wednesday to the devastated central city of Tacloban.

"As the debris is cleared, they are finding more dead bodies. We experienced that for ourselves," she told reporters.

Amos visited Tacloban to inspect the progress of the UN-aided rehabilitation effort and check on the condition of survivors of one of the strongest typhoons ever to hit land.

The government's National Disaster Risk Reduction and Management Council confirmed bodies are still being found.

"Sometimes they find two or three a day, then there are days where they find none," its spokesman Reynaldo Balido told AFP.

The latest casualty figures were a month old and did not reflect any subsequent corpse retrievals as the authorities work to reconcile the numbers, he added.

Balido said residents have learnt to adapt to the sight of newly found corpses.

Haiyan raked across the central Philippines on November 8 last year, wrecking 1.1 million houses and displacing more than four million residents of some of the country's poorest provinces according to the UN.

The worst damage was inflicted by huge tsunami-like surges of seawater into Tacloban and other coastal communities.

Amos said Tacloban survivors need more help.

"They are many people trying to live in their original (ruined) homes. They put up a tarpaulin as a roof and put some wood on the side and that's not good enough. It won't stand up to a storm," she said.

The UN was also concerned about the welfare of more than a million farmers after 30 million coconut trees were destroyed, she said.

Replacement trees will not bear fruit for another six to eight years, Amos said.

About 30,000 small fishing boats were also destroyed or damaged, she added.

To help these people, the UN asked aid donors for $788 million in December, but Amos said only just over $362 million has been raised.

"Signs of devastation are still evident but so too are signs of progress," she added.