The Vanuatu Meteorological Service has said that the nation has been battered by a category five tropical cyclone, packing winds of up to 250 kilometres per hour.

Cyclone Pam has caused flooding in parts of the country.

The Vanuatu Meteorological Service said red alerts were in place for Sanma, Penama, Tafea, Malampa and Shefa provinces.

Some unconfirmed reports claimed that 44 people have died as a result of the storm but only six deaths have been confirmed so far.

The centre of Tropical Cyclone Pam cyclone has passed Port Vila and is moving in a southerly direction at about 27 kilometres per hour. The island of Erromango was affected as the cyclone tracked south.

Vanuatu's Meteorological Services said "very destructive hurricane force winds" of 250 kilometres per hour were affecting Shefa and Tafea provinces. It warned of torrential rainfalls, flash flooding, landslides and storm surge.

Reports said that power and water outages were caused in the capital, Port Vila due to storm.

Nichola Krey, head of the humanitarian affairs at Save the Children, was in touch with staff in Vanuatu before communications got snapped. "Temporary dwellings, which most Vanuatu people live in, corrugated iron houses have been completely annihilated," she said.

"Nothing left in terms of local housing. Some of the larger structures are also gone as well. We are expecting a fairly chaotic scene this morning," she added.

Oxfam spokeswoman Helen Szoke said the organisation was unable to get in touch with its staff on the ground since last night. She however added that before communications shut down, the staff at the gounnd were giving harrowing reports of the impact of Cyclone Pam.

"Our staff in Port Vila, they're saying the noise was incredible, just the strength of the wind," she said.

"It's going to be some days before we know the full extent to the damage that's been done."