BANGKOK - THAILAND'S opposition Democrat Party said on Saturday it had gained the support of five parties in the ruling coalition and would try to win over some main party lawmakers as well in its bid to form a new government.

The courts disbanded three of the parties, including the biggest, the People Power Party (PPP), on Tuesday for electoral fraud and their leaders had to step down as ministers.

Parliament must elect a a new premier and parties are jostling for power.

Lawmakers from the disbanded parties have simply switched to 'shell' parties and so the ruling coalition could in theory remain in place, albeit with parties of different names.

But Democrat Party spokesman Buranaj Smutharaks said his party hopes to prevent that.

'The Democrats are offering to lead a new coalition, with the support of five parties, and we are open to more people joining us,' he said, adding the party would hold a news conference later on Saturday.

The Democrats and the five small parties may just be able to command a majority in parliament.

The court ruling on Tuesday came as the extra-parliamentary People's Alliance for Democracy (PAD) was blockading Bangkok's two main airports, stranding hundreds of thousands of tourists and disrupting cargo traffic as part of its campaign to oust the government.

The PAD ended the blockade after the ruling but has made it clear it will resume its campaign if it doesn't like the new government. It accused the PPP of being a front for former Prime Minister Thaksin Shinawatra, ousted in a coup in 2006.

According to figures from parliamentary officials, the Democrats, with 165 seats, plus the five coalition parties it has wooed, would have a total of 229 votes in parliament.

That would trump the 219 of the People Power Party, or the Puea Thai party that has succeeded it, as long as all members of the five small coalition parties came over.

Some members of the old PPP have said they may not join Puea Thai, and they may also be enticed to join the Democrats.

Adding to the uncertainty, Thaksin's ex-wife has just returned to Thailand from exile amid speculation in the local press she has come back to sort out problems inside Puea Thai.

Despite several arrest warrants, police did not detain Potjaman Shinawatra because her appeal against a three-year jail sentence for tax evasion was in progress, police said.

The new party is due to choose its leader on Sunday.

A spokesman for Potjaman said she had returned to Thailand to see her sick mother, and that it had nothing to do with politics.

She was divorced from Thaksin in November after 32 years of marriage. No explanation has been given.

Thailand has been in political crisis for three years, with Bangkok's royal and military elites pitted against Thaksin and then his allies who formed a government at the start of this year.

Thaksin remains in exile and his whereabouts are unknown.

The couple lost their London base after Britain revoked their visas. -- REUTERS