Severe tropical cyclone Lola is passing over Pentecost Island and is forecast to make landfall on Malekula Island, Fiji Meteorological Service says.

Lola is now a category four cyclone with average wind speeds close to the centre of 185km/h with gusts reaching 260km/h.

It dropped from category 5, the highest cyclone category, Tuesday night before making landfall.

Meteorologist Samisoni Waqavakatoga says the cyclone may drop slightly more in strength but would most likely remain as a category 4 cyclone.

The cyclone was moving southwest slowly at 15km/h, says Waqavakatoga.

"For a category 3, 4, 5, slow moving, it will bring more destruction compared to category one or two."

Models show parts of Vanuatu could get up to 300mm of rain over 24 hours from the cyclone, says Waqavakatoga.

Waves close to the island are also expected to reach up to 5 metres.

The intensity of the cyclone is forecast to drop as it passes over Malekula Island, he says.

Vanuatu on high alert

Vanuatu's National Disaster Management Office (NDMO) has activated offices in six provinces as Tropical Cyclone Lola bears down on the eastern island of Pentecost.

The Vanuatu Met Service downgraded Lola to a category 4 on Tuesday but says the massive storm will still pack a severe punch when it makes land.

NDMO operations manager Rocky Neveserveth says it activated the offices to be ready to carry out a rapid assessment after the cyclone.

The capital, Port Vila, is on red alert and all government offices, markets, and banks are closed until further notice.

RNZ's Pacific Vanuatu correspondent says he has had reports from people on the island of Motalava in Torba province on Tuesday that winds damaged banana trees.

He says he's been told the sea around the island is rough, and in some parts of the island waves are washing inland.

At 2am Wednesday local time, the cyclone was about 30km west of the Pentecost, the Vanuatu Meteorological and Geo-Hazards Department said in its latest warning.

Winds close to the centre were estimated at 165km/h gusting to 189km/h within 16 nautical miles from the centre of the system and expected to affect the islands of Torba, Sanma, Penama and Malampa in the next 24 hours, the meteorological office warning said.

Very destructive hurricane force winds of 230km/h gusting to 320km/h were expected to affect Torba, Sanma, Penama and Malampa in the next 24 hours.

Destructive storm force winds of 185km/h gusting to 265km/h were within 90 nautical miles from the centre of the system and would affect Torba, Sanma, Penama, Malampa and Shefa later in the day.

-RNZ.