Tsunami threat passes after Vanuatu quake

Officials have wound back an initial tsunami threat issued after a large earthquake struck off the coast of Vanuatu.

The Pacific Tsunami Warning Centre said on Sunday evening the danger had largely passed and cancelled an earlier warning of a possible tsunami as a result of the quake, which was initially measured at a magnitude of 7.2 but later revised down to 6.9.

The quake was also deemed to be deeper that first thought - 33km as opposed to 10km, Kanoa Koyanagi, a geophysicist at the Pacific Tsunami Warning Centre in Hawaii told Reuters.

Koyanagi said experts expected waves of no larger than 30 centimetres, well below tsunami levels, from the quake which struck 151km north northwest of Vanuatu's Santo island.

"Based on all data available ... the tsunami threat from this earthquake has now mostly passed," the centre said in a statement.

The Vanuatu Meteorological Services, a government department, said there were no reports of damage.

Anna Romero, a doctor staying at a hotel near the town of Luganville on Santo, told Reuters she felt the tremor, but saw no signs of damage.

Earthquakes are common in the area and even large tremors often cause no tsunamis.

A 7.3 magnitude quake struck off Vanuatu in October and a 6.3 quake struck in December without causing any damage.