* Government insists election has to be on Feb. 2
* Protesters are blockading main roads, reject election
* Protesters want electoral system altered before election
* Some threaten blockade of bourse, air traffic facility
By Amy Sawitta Lefevre and Andrew R.C. Marshall
BANGKOK, Jan 15 (Reuters) - Thailand's government stuck to a plan for a February election on Wednesday despite mounting pressure from protesters who have brought parts of Bangkok to a near-standstill, and said it believed support for the leader of the agitation was waning.
Some hardline protesters threatened to blockade the stock exchange and an air traffic control facility if Prime Minister Yingluck Shinawatra had not stepped down by a deadline media said was set for 8 p.m. (1300 GMT).
There was no apparent movement as the deadline came and went.
The unrest, which flared in early November and escalated this week when demonstrators occupied main intersections of the capital, is the latest chapter in an eight-year conflict.
The political fault line pits the Bangkok-based middle class and royalist establishment against the mostly poorer, rural supporters of Yingluck and her brother, Thaksin Shinawatra, a former premier ousted by the military in 2006 who is seen as the power behind her government.
Yingluck invited protest leaders and political parties to discuss a proposal to delay the general election, which she has called for Feb. 2, but her opponents snubbed her invitation.
After the meeting, the government said the poll would go ahead as scheduled, and it derided the leader of the protest movement, Suthep Thaugsuban.
"We believe the election will bring the situation back to normal," Deputy Prime Minister Pongthep Thepkanchana told reporters. "We can see that the support for Mr. Suthep is declining. When he is doing something against the law, most people do not support that."
Speakers at protest sites across central Bangkok have given the impression Yingluck is worn out and eager to quit. But she seemed relaxed and cheerful at the meeting, which was held inside an air force base near Don Muang International Airport.
Her senior officials stressed the caretaker government had no legal powers to postpone or cancel the election and stressed that even an imperfect poll was better than none.
"The ballot box doesn't solve everything, and she knows that. But at least that's the right step," Suranand Vejjajiva, secretary-general to the prime minister, told Reuters.
AIR TRAFFIC CONTROL ASSURED
The protesters say they will occupy the city's main arteries until an unelected "people's council" replaces Yingluck's administration.
Thaksin's rural and working-class support has ensured he or his allies have won every election since 2001 and Yingluck's Puea Thai Party seems certain to win any vote held under present arrangements.
The protesters want to suspend what they say is a democracy commandeered by the self-exiled billionaire Thaksin, whom they accuse of nepotism and corruption, and eradicate the political influence of his family by altering electoral arrangements.
There was no sign of trouble at the two targets named by hardliners in the protest movement, the stock exchange and the central Bangkok offices of AeroThai, which is in charge of air traffic control communication for planes using Thai air space.
AeroThai said it had back-up operations to ensure no disruption to air travel if its control centre was shut down.
Suthep's supporters have blockaded at least seven big Bangkok intersections and are also trying to stop ministries from functioning, forcing many to remain closed, with civil servants working from back-up facilities or from home.
Yingluck herself has been unable to work from her offices in Government House since late November.
Demonstrators marched to the home of Energy Minister Pongsak Raktapongpaisal carrying a coffin with his name on it, ASTV news reported. They handed one of his aides a note demanding that he cut LPG prices and resign, it said.
According to the official Twitter account of National Police spokesman Piya Utayo, an off-duty policeman dressed in civilian clothes was attacked and had his gun taken off him by about 10 protesters at a rally near the Energy Ministry.
"RED SHIRTS" TO STAY OUT OF BANGKOK
The latest protests have been less violent than a spasm of unrest in 2010, when troops were sent in to end a two-month protest in central Bangkok by "red shirt" Thaksin supporters. More than 90 people died during those protests.
Thaksin, who turned to politics after making a fortune in telecommunications, redrew Thailand's political map by courting rural voters. He lives in exile to avoid a jail sentence handed down in 2008 for abuse of power.
There have been relatively few factional clashes in this upsurge of unrest with the government keen to avoid confrontation. Government supporters said they held protests on Monday and Tuesday in provinces neighbouring Bangkok but had no plans to demonstrate in the city.
"All we ask is that Prime Minister Yingluck does not resign," said Worawut Wichaidit, spokesman for the pro-government United Front for Democracy Against Dictatorship.
"If (Suthep) and his group achieve their goal ... the outcome would be similar to a coup, and we all saw what happened the last time there was a coup," Worawut said, referring to instability and factional strife in the years that followed the last army takeover in 2006.
It is widely thought that, if the agitation grinds on, the judiciary or military may step in. The military has staged or attempted 18 coups in 81 years of on-off democracy, although it has tried to stay neutral this time and army chief Prayuth Chan-ocha has publicly refused to take sides.