Tonga Power says it could take months to fully repair the fragile electricity network in the northern islands of Vava'u.
The area was lashed twice by the cyclone, which hit homes and destroyed key infrastructure.
Now, after the double hit from the storm, residents have been left on edge.
"Right now me and my family are hoping the cyclone won't come again from Fiji," says Villiami Latu.
The immediate focus is cleaning up, and the country's already primitive electricity network could take months to repair.
"It's very basic; that's the problem we face," says Tonga Power's chief executive, Robert Matthews. "We have very limited equipment to do the work. So for example, we only have one bucket truck for the whole island and one small crane. So we can't send out multiple crews to multiple locations."
Even the island's army barracks copped a battering and will need to be demolished.
But despite the damage, the community knows it escaped the worst.
"Tonga was incredibly lucky to have a cyclone pass through twice and to suffer the amount of damage it did," says New Zealand High Commissioner in Tonga Sarah Walsh. "It was not as bad as what we first thought it might be."
The biggest worry now is the widespread damage to food crops.
"The breadfruit trees were completely uprooted, banana trees were knocked over, the taro plants were damaged. What the Tongans will be looking to do is replanting," says Ms Walsh.
But while replanting takes place, officials say residents will run out of food.
"Some crops have been totally uprooted," says Sela Fa'u of Tonga Public Health. "I think in the next month or two there will be a food shortage."
New Zealand has committed $60,000 to assist Tonga. Part of that has been spent on charter planes to carry out aerial damage assessments, while funding for looming food insecurity and preventing the spread of Zika virus will also be considered.