Thailand's first-ever referendum has endorsed the country's 18th constitution that promises to weaken the political party system and strengthen the hand of the bureaucracy and military, initial results showed Monday.

A count of 93 per cent of the ballots cast in Sunday's plebiscite, found that 58.3 per cent voted yes, 41.7 per cent no and the remainder were invalid, said Election Commission secretary general Sittipol Paveechaikorn.

About 25 million out of 45.6 million eligible voters, or about 55 per cent, participated in the referendum. Official results will be announced by 4 pm Monday, Sittipol said.

But the initial results also show Thailand's north-eastern region, the most populated and poorest, voting 63 per cent against the charter, which many have seen as a popularity contest between the military and the former populist regime of Thaksin Shinawatra who was deposed by a coup September 19.

"The military is satisfied with the people's acceptance of the constitution," said Army General Sonthi Boonyaratkalin, who heads the junta that ousted Thaksin.

Political analysts, however, said the results indicate that Thailand remains deeply divided.

The north-east was Thaksin's stronghold during his six years in power between 2001 and 2006, and the region, home to nearly half of Thailand's population, still supports him and his Thai Rak Tahi Party, observers said.

"This vote shows that the polarization of Thailand is entrenched," said Thitinan Pongsudhirak, director of Thailand's Institute of Security and International Studies. "It signifies a deeply divided country."

Thailand's other four regions - Bangkok, the south, the central plains and the north - supported the charter.

The endorsement of the constitution will pave the way for a general election scheduled in December.

Had it been rejected, Thailand's junta - the self-styled Council of National Security (CNS), would have chosen one of the country's 17 past constitutions instead.

The September 19 coup discarded Thailand's 1997 constitution, deemed by many to have been the kingdom's most liberal and participatory charter to date.

The 1997 charter, however, gave rise to Thaksin, a billionaire populist politician, who became one of the most divisive figures in Thailand's recent political history.

Thailand has been in political upheaval since January 2006, when a strong anti-Thaksin movement took off in Bangkok and built in force until it culminated in the September coup.

Thaksin, a former telecommunications tycoon, first came to power in the 2001 general election on a populist platform and slick campaign gimmicks that won him the backing of the rural poor and disgruntled urban middle class.

A good delivery record on campaign promises won his Thai Rak Thai (Thais Love Thais) Party an overwhelming majority in the 2005 polls, giving Thaksin an unprecedented parliamentary majority that allowed him run roughshod over over the opposition and independent bodies established by the 1997 charter to provide checks and balances to the executive.

Abuses of power eventually led to Thaksin's downfall, at the hands of the military, last year. Thaksin, who faces various corruption charges and an arrest warrant in Thailand, is residing in London where he has purchased several properties and the Manchester City football club, which unexpectedly beat Manchester United in a match Sunday.

While the 1997 constitution was written to strengthen the political parties against their traditional downfalls, weak and corrupt coalition governments that led to military coups, the 2007 draft charter essentially strengthens the hand of the bureaucracy, including the military, at the expense of the political parties.

There are good points to the new charter, such as the articles that increase the people's participation in politics.

But the new constitution's pro-military content, especially article 309, which grants an amnesty for coup makers and legitimizes the military's future role as a overseer of Thai politics, deeply worries pro-democracy activists.

Opponents to the 2007 charter criticize it as a step backward for Thailand's political party system, and a revival of the rule of the traditional elite - the bureaucracy, the military and the constitutional monarchy.