Lack of power and no running water in Tonga is hampering the cleanup effort, locals say.
Category four Tropical Cycle Gita ripped through the island nation on Monday evening leaving thousands of homes damaged.
The Red Cross said there were still about 4000 people staying at evacuation centres because their homes were unfit.
AUT PhD student Tony Fakahau said he was in Tonga researching vulnerable communities and some of his participants were those in the centres.
"Many of them lived in pretty much homes with just a tin roof on top of them," he said.
"I went out again to have a look at some of the homes just to see how they were and those homes have disappeared."
Most of the crops on the main island of Tongatapu were damaged and although families could cope, it was the long-term shortage that would hit families the hardest, he said.
"Every family relies on the land - taro, yam, kasava ... coconut and also the fruit. The storm pretty much blew everything off trees [and] uprooted crops."
He worried food would get more expensive and there would be an increase in imports to meet the shortfall, he said.
The most pressing worry was the lack of power and water supply, Mr Fakahau said.
"The water systems in most of the villages rely on electricity - the two go together," he said.
"Without water you're going to be affecting hygienic issues and the danger of dengue fever is getting worse."
'Half the trees have just been demolished'
Veitongo resident Derek Leonard runs a coffee plantation and said he did not have power or water and did not expect it to come on for weeks.
But he was one of the lucky ones, he said.
"I have a water tank that I can actually dip a bucket into and grab that out of. Today I had a lovely rain shower just underneath the guttering."
Half the crops at his plantation were destroyed, he said.
"My drying shed is pretty much wrecked and a lot of plants, a whole lot of crops and ... half the trees have just been demolished."
Nearby properties weren't spared either, he said.
"Quite a few of them have lost roofs. Some of the smaller shops are just completely demolished. The roadways been cleared now but there's just build up of vegetation like huge trees have been knocked over and it's just decimated."
The Defence Force flew agriculture tool kits, family hygiene kits, collapsible water containers, tarpaulins, generators and chainsaw packs to Tonga this afternoon.
It hoped the supplies would provide basic power, water and sanitation, it said.
The Red Cross evacuation centres would be open again tonight.