Terrified survivors of a super typhoon that killed thousands in the Philippines last year were on Wednesday preparing for a powerful new storm, as authorities scrambled to find safe evacuation centres.

Typhoon Hagupit was building strength in the Pacific Ocean as it moved towards central Philippine islands where impoverished farming and fishing communities are yet to recover from the previous devastation.

In Tacloban, one of the cities worst-hit by Super Typhoon Haiyan 13 months ago, residents cleared shop shelves of canned food, candles, nappies and other essentials, well ahead of Hagupit's forecast landfall on Saturday.

"It's not raining yet but people are panic buying after hearing about the typhoon warnings on television and radio," Helen Buena, a clerk at a small supermarket in Tacloban, told AFP.

"They're taking goods by the dozen, two dozen."

Hundreds of thousands of people still live in vulnerable coastal areas of Tacloban and other areas that were ravaged by Haiyan, which killed or left missing more than 7,350 people.

"Our problem is, we don't have enough evacuation centres," Tacloban vice mayor Jerry Yaokasin told AFP.

He said some of the schools normally used as evacuation centres had yet to be rebuilt after being destroyed in Haiyan, while others were too close to the coast.

Haiyan, the strongest typhoon ever recorded on land with winds of over 315 kilometres (196 miles) an hour, tore across a corridor of the central Philippines that was already among the nation's poorest regions.

It also generated storm surges more than two storeys high that swept kilometres inland in some places, flooding schools, gymnasiums and other buildings used as evacuation centres.

Many people were killed as they sheltered in the evacuation centres.

Yaokasin said a top priority as Hagupit approached was helping about 17,500 Haiyan survivors still living in tents or temporary shelters along coastal areas of Tacloban.

He said authorities were trying to identify new evacuation centres for them far from the coast.

But the government has said roughly one million people live in unsafe housing across the areas hit by Haiyan, and that plans to build new homes for them will take years.

- Fear -

"I can't concentrate at work because I keep checking the (disaster alert) websites," Tacloban resident Ailyn Metran told AFP.

She said staff at the government health insurance company office where she worked had been told to pack away computers and documents ahead of Hagupit.

Weather forecasters said Hagupit was not expected to be as strong as Haiyan, with wind gusts expected to peak at 170 kilometres an hour, however storm surges one-storey high were possible.

It was forecast to start bringing rains to the eastern Philippines on Friday, and was on track to make landfall on the eastern island of Samar on Saturday afternoon.

But with Hagupit still hundreds of kilometres away, forecasters said it could still turn north towards Japan and miss the Philippines completely.

The Philippines is hit by about 20 typhoons or tropical storms each year.

Scientists have warned global warming is increasing the strength and frequency of extreme weather events such as the typhoons that regularly hit the Philippines.

The ferocity of Haiyan was consistent with man-made climate change, according to the United Nations' weather agency.