Key Points:

Prime Minister John Key last night sent the Air Force to help evacuate New Zealanders from Bangkok.

But his decision came after the Government initially appeared to have no contingency plan.

An Air Force Hercules left Whenuapai last night, making New Zealand the first country to call in its military to help citizens stranded by unrest in Thailand.

The number of foreigners caught in the chaos has been put at up to 350,000.

Fears of violent clashes, or worse, are growing.

"It now seems that violence cannot be avoided," the Bangkok Post said in an editorial. " Some even predict what has been unthinkable for 700 years, a civil war."

Lensie Deane, a 72-year-old New Zealand grandmother stranded in Bangkok since arriving on a stopover on Thursday, said Mr Key's action was good, but "very late".

Mrs Deane said she would continue to try to find her own way out, but if she couldn't, "I will be the first in the queue."

She described failed attempts by embassy officials to get her out, overloaded phones at the airlines and queues starting outside their offices before 6am.

"I can't see a Thai Airways person calling me up and saying: 'we've got a ticket for you'."

Ben Bradley, a 24-year-old on his way to London, said it was "every man for himself" and he had managed to get a flight to Frankfurt on Friday.

Thai judges yesterday ordered Prime Minister Somchai Wongsawat's ruling People Power Party (PPP) to be disbanded after it was found guilty of vote fraud.

The Constitutional Court also barred the party's top leaders, including Mr Somchai, from politics for five years, raising the risk of clashes between his supporters and anti-government protesters who are blockading the capital's two airports.

The yellow-shirted People's Alliance for Democracy (PAD) demonstrators at the airports have been seeking to topple Somchai, whom they accuse of being a pawn for his brother-in-law, former premier Thaksin Shinawatra, ousted in a 2006 coup and now in exile.

A grenade was fired from a flyover near the domestic airport hours before the court hearing, killing one anti-government protester and wounding 22 people.

The electoral fraud case was to have been heard at the Constitutional Courthouse in Bangkok yesterday, but authorities moved it after hundreds of red-shirted government supporters surrounded the court building.

The ruling on allegations of vote fraud in last December's election will not necessarily mean a snap election as many PPP MPs will switch to a new "shell" party already set up.

Mr Key began yesterday unable to give a clear indication of what could be done for the up to 300 New Zealanders stranded in Bangkok.

Asked if he was confident he could get them out should the violence escalate in the next hour, he replied: "I don't know the answer to that."

The Australian Government has started running flights with Qantas. Mr Key was still deciding whether to run a similar charter flight, use the Air Force, or work with Australia or other friendly countries.

Later in the day, he announced he had decided to "pre-position" the Hercules in Malaysia ready to get New Zealanders out.

The time it will take the Hercules to get there and then get into Thailand meant there was a 48-hour delay, Mr Key said.

"I think it would be irresponsible of me not to act today because every day I don't act is another 48 hours."

Mr Key said commercial flights remained the best way for New Zealanders to get out, but he was sending the Air Force because he was not satisfied the commercial option would work.

"I am distressed about the number of New Zealanders in Bangkok who cannot find a credible pathway out."

Mr Key said he would decide whether to use the Hercules once it arrived. If it was used, it would ferry 65 passengers at a time out of the U-Tapao military airbase near Bangkok to Kuala Lumpur.

"If we are in a position where there is no obvious route for New Zealanders out, there's a large number there that want to leave and we continue to see the stand-off between the warring Thai factions, we are likely to deploy."

Mr Key had to send the Hercules as both the Air Force's bigger and faster Boeing 757 planes are under repair.