As Vanuatu and Fiji emerge from a trail of destruction left by Tropical Cyclone Harold, Tonga is bracing for damage as the category five storm passes the island kingdom.

Key points: The category five cyclone is tracking south-east of Tonga today

The category five cyclone is tracking south-east of Tonga today It has wreaked havoc in the Solomon Islands, Vanuatu and Fiji over the past week

It has wreaked havoc in the Solomon Islands, Vanuatu and Fiji over the past week Damage in Fiji was more severe than expected

The cyclone, with wind gusts of up to 285 kilometres per hour near its centre, passed by the south of Tonga this morning (local time).

The Tongan Meteorological Service has issued warnings for the Tongatapu and 'Eua island groups with expectations of hurricane-force winds of up to 117kph.

There are also warnings of gale force and strong winds for the Ha'apai, Tele-ki-Tonga and Tele-ki-Tokelau island groups and Vava'u, Niuatoputapu and Niuafo'ou islands.

The meteorological service said it expected a damaging ocean swell to batter all of Tonga as the storm moves south-east.

The cyclone is bringing heavy winds and strong tides to Tonga. ( Supplied: Japanese Meteorological Agency / Himawari-8 / Tongan Meteorological Service )

Tongan National Emergency Management Office (NEMO) has advised people to stay away from coastal areas and avoid sea travel until the storm passes.

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It is forecast to move out of Tongan waters and downgrade to a category three storm by 7:00pm (local time).

The cyclone is passing south-east of Tonga today. ( Supplied: Tongan Meteorological Service )

'I can't see how they can survive'

In Vanuatu, the devastation is widespread. Power and water supplies are still down and the majority of homes have been damaged in some way, leaving many homeless.

Christina Boelulvanua and her family were among the thousands of people who fled volcanic eruptions on Vanuatu's Ambae island back in 2018.

But the tropical cyclone has smashed her new life to pieces.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 1 minute 11 seconds 1 m 11 s Power and water supplies are still down in Vanuatu and the majority of homes have been damaged.

"It's so depressing for me and the family. I ran away from the volcano with my kids thinking 2020 would be safe but then came Cyclone Harold," she said.

Ms Boelulvanua lives in Banban, a community set up for volcano evacuees in the island of Santo.

Nearly everything in Banban has been flattened by Harold's winds. Every house has been damaged and food gardens are wiped out.

"Now it's all gone. All the bananas are down, yams are down. So it will take time before we start all over again," she said.

Like many in Vanuatu, Ms Boelulvanua depends on her garden to feed her family.

She told the ABC her family would eat the scraps the cyclone has left them, but she doesn't know what they'll do once it's finished.

"Some people who have paid jobs can still survive from buying food from the shop, but [for] others who depend on food crops, I can't see how they can survive," she said.

Fiji damage more severe than expected

Fiji emergency management authorities are continuing to monitor flood-affected roads. ( Twitter: Fiji National Disaster Office )

Fiji has begun assesses the damage left by Harold, which moved out of the country's waters overnight.

Images and vision have emerged showing widespread flooding on the main island Viti Levu.

Residents have also reported that roofs were ripped off buildings and roads blocked by fallen trees.

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Fiji Red Cross director general Ilisapeci Rokotunidau told the ABC's Pacific Beat program the initial damage from the cyclone was far more severe than anticipated.

"We didn't predict the amount of saturation there was on land. The floods came up quite quickly and into areas we didn't anticipate," Ms Rokotunidau said.

Naziah Ali, who lives in the town of Ba — located in the north-west of Viti Levu — told Pacific Beat her town was engulfed.

"The town is flooded, most of the shops that you see open on a Wednesday have been closed and boarded up," she said.

"I can already envisage how much damage there's going to be to goods and other materials people have in their shops."

Residents of Makadru, in Fiji's southern Lau island group, were particularly hit hard by Harold. ( Supplied: Neville Koop )

She added that she saw widespread crop damage to nearby farms and sugar cane fields.

Coronavirus throws spanner in the works

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The damage from Harold has made Fiji's management of coronavirus more complex. The country has 15 confirmed cases.

"We are doing all of this amid COVID-19 restrictions, so a lot of the [country's] movement has been restricted," Ms Rokotunidau said.

"One of the things we have stressed to our volunteers is their own personal safety as they prepare to [help families]."

She said she hoped the Australian Red Cross would donate personal protective equipment (PPE) to Fiji's Red Cross volunteers as they assist in the recovery effort amid COVID-19.

The Australian Government has provided the Solomon Islands with more than $99,000 of emergency assistance funds, while New Zealand has also joined Australia in providing more than $480,000 in financial assistance to Vanuatu.

A defence jet will leave Australia later today to deliver cyclone relief supplies to Vanuatu.

Australia has also confirmed an offer to Fiji of damage surveillance and humanitarian relief supplies.

Australian Foreign Minister Marise Payne told a press conference this morning that officials were "assessing" what immediate impact Cyclone Harold was having on Tonga.

"We stand ready to provide what further help we can to our Pacific family in whatever ways we can," she said.

Australia to provide supplies

The cyclone struck Vanuatu with winds of up to 285 kph. ( ABC News: Dan McGarry )

Australia is working with the Red Cross and other NGOs to provide supplies like tents and water containers in Vanuatu.

It is also helping with damage-assessment flights.

The ABC has been told the situation is "grim" with fears the damage in some places has been as bad as Cyclone Pam, which hit Vanuatu in March 2015, killing at least 15 people and leaving the country with a damage bill of nearly $600 million, more than half of the country's annual GDP.

The Australian High Commissioner to Vanuatu was aboard one of the damage-assessment flights and she was joined by the Vanuatu country director for the NGO World Vision, Kendra Gates Derousseau.

"Houses were essentially pulled to pieces rather than just wind damage. It was catastrophic," Ms Gates told the ABC's Pacific Beat.

In Sanma province, in western Vanuatu, structures have been decimated in villages across the region. ( ABC News: Dan McGarry )

Ms Gates Derousseau said that eight of her staff "had lost everything", including one pregnant staff member who had to run for cover with her family.

"[She] described [being] in the middle of the cyclone, having to take her two young children by the hands and run about 100 metres to another house because a large tree had fallen on her house," she said.

With the double-whammy of managing coronavirus mitigation and cyclone recovery, Ms Gates Derousseau said Vanuatu's full recovery would take years, and would need international help.

"Given the COVID-19 crisis, I would anticipate that at least the economy will take many years to start again, particularly because Santo [Island] was a massive tourist destination," she said.

"The north of the island is also the big agricultural centre. So there will be significant damages sustained because of the loss of crops and the loss of the ability to both internally and externally export.

"[But] the Vanuatu people are proving themselves resilient, [and] they will need international assistance to continue with that journey."