Andrew Robinson, of Auckland, arrived in the hard-hit town of Dulag, on the east coast of Leyte Island, 12 days after the devastating cyclone swept through the Southeast Asian nation in early November.
Relief agencies and government departments were responding well to the immediate needs of the humanitarian crisis, Mr Robinson said.
But he and fellow aid workers are concerned about a potential food shortage early in the new year.
''Many of the people living here depend on the coconut industry for their livelihoods,'' Mr Robinson said.
Almost all the coconut trees, however, have been destroyed. It will be a decade before replanting produces the next sizeable coconut harvest.
''We are a bit concerned about what will happen in two or three months' time if the food being brought in stops and people run out of money,'' he said.
''People here do need more food, long term.''
More than 6000 people died as a result of Haiyan, the Philippines' most deadly storm on record. Most of the deaths were on Leyte and neighbouring Samar Island. More than half a million families are without housing and many people have lost livelihoods.
Mr Robinson is working for TearFund and Swiss-based Medair, which are members of an alliance of international aid and development agencies co-ordinating their response efforts. The agencies are leading the provision of temporary shelter in Dulag, where more than 80% of homes were destroyed.
Dulag is 30km south of the provincial capital Tacloban, where more than 20 bodies were being recovered from debris in Tacloban, it was reported this month. `Mr Robinson has been struck by the gratitude of the Filipinos.
''There are lots of signs along the roadside thanking agencies for help. I've never seen that before,'' he said.
He was also impressed by the resilience of the locals who were trying to clear debris in their neighbourhoods.
''But I know that underneath those smiles is a lot of loss and grief,'' he said.
Rebuilding will not be a ''quick fix''.
''It needs ongoing commitment and long-term investment from the Philippines Government and the international community.''
