The cyclone made landfall on the largest island in Vanuatu, Espiritu Santo, on April 6 before hitting the Solomon Islands, Fiji and Tonga. The UN cited media reports saying the storm left more than two dozen people dead, and destroyed homes, buildings and crops in the four countries, the Nambucca Guardian reported.
UN spokesman Stephane Dujarric said secretary-general Antonio Guterres expressed "deep solidarity with the people of the Pacific as they face the impact of this cyclone along with other climate-related challenges".
UN humanitarian chief Mark Lowcock, who announced the release of the funds for Vanuatu this week, said: "Thousands of people urgently need shelter, water and food to survive."
Meanwhile the Ministry of Education and Training has reported that about 1010 schools have been damaged or destroyed in cyclone affected areas.
The once-lush forest cover of the island of Malo has been completely denuded. Nearly every tree lost major limbs, writes Dan McGarry for The Guardian newspaper.
Many were snapped at the trunk. Even cyclone-adapted coconut trees were strewn about like matchsticks. Schools and homes were destroyed.
On Monday Vanuatu was rocked by Cyclone Harold, the second category-5 storm to hit the nation in five years.
The cyclone, which formed off Solomon Islands and led to the deaths of 27 people who were swept off a ferry in rough seas, went on to flatten buildings and cause severe flooding in Fiji and Tonga. But it passed through the north of Vanuatu when it was at its strongest.
A small, single-engine plane took off from Vanuatu's capital of Port Vila on Wednesday to survey the impact on the northern islands of the country.
With communication lines down, news up until this point about the extent of the damage has been sparse, but as the plane flew over Malo, then Aore, and finally Santo, the largest island in Vanuatu, it was clear that the cyclone had cut a deadly path.
Santo, the setting for the book that inspired the Rogers and Hammerstein classic musical South Pacific, was no longer recognisable. Once lush and verdant, it is now barren landscape, sun-burnt and severe.
The majority of Santo's 40,000 inhabitants inhabit the southern coastal stretch of the 100km-long island, which was impacted directly by the storm.
For lord mayor Patty Peter, the experience was overwhelming. In an emotional phone call to media in Port Vila Tuesday he said, "We urgently need water, food and shelter at the moment. Many have lost their homes. Schools are destroyed. Electricity is down. I'm urgently calling for help. This is one of the worst experiences of my life."
He later confirmed that food and water were being distributed, but "just for today and tomorrow. That's all that we can do".
The town has shrugged off smaller cyclones countless times in the past. "But this one, like, it's a nightmare. It's a nightmare for all the people in the northern islands," said Peter.