The 7.3-magnitude earthquake struck off the main island on Tuesday, toppling concrete buildings in the capital Port Vila and setting off landslides.

It damaged water supplies, knocked out mobile networks and halted operations at the capital's main shipping port.

Twelve people have been confirmed killed so far, according to government figures relayed late Friday by the United Nations' humanitarian affairs office.

The dead include two Chinese, one Thai, and one French national, according to the UN update and embassy officials.

Vanuatu has declared a seven-day state of emergency and a night-time curfew.

But commercial flights, halted since the quake, will resume on Sunday, Airports Vanuatu said, allowing the return of holidaymakers to the archipelago of 320,000 people, which sits in the Pacific's quake-prone Rim of Fire.

"Following close consultations with all our airport agencies, we are pleased to announce that we will be reopening Port Vila International Airport to commercial airline operations tomorrow," it said in a statement.

"We encourage stranded passengers both within Vanuatu and abroad to contact your relevant airlines to confirm details of your travel plans."

Tourism directly and indirectly contributes to more than half of the country's economic activity, said Glen Craig, chair of the Vanuatu Business Resilience Council.

"It's important the world knows we're going to be back open for business," Craig told AFP.

"The quake has obviously been terrible but the damage is localised. Life goes on as usual for 99 percent of the people here and the many villages outside Port Vila.

"They have livelihoods and it's so important that we don't suffer an economic disaster in the wake of this."

Engineers have certified the infrastructure at Port Vila's Bauerfield International Airport, while aviation fuel supplies have been cleared as uncontaminated, Airports Vanuatu said.

- Quake damage 'extensive' -

The quake has displaced more than 1,000 people -- many now with other households or in evacuation centres, the latest UN report said, citing Vanuatu disaster management officials.

There are critical needs for electricity, clean water, food assistance, hygiene and sanitation and shelter, it said.

"Infrastructure damage is extensive, with landslides obstructing road access in Efate and the outer islands, including routes to the seaport," the report said, referring to Vanuatu's most populous island.

"The authorities have sealed off Port Vila's Central Business District, declaring it off-limits to the public until engineering assessments are completed."

Australia and New Zealand have dispatched more than 100 personnel, along with rescue gear, dogs and aid supplies, to help hunt for trapped survivors and make emergency repairs.

A total of 424 Australian citizens have been evacuated on Royal Australian Air Force flights, with two further flights scheduled for Saturday.