* Opposition Democrats challenge election in court
* Election Commission probes possible campaigning irregularities
* Bangkok protests appear to dwindle (.)
By Amy Sawitta Lefevre
BANGKOK, Feb 4 (Reuters) - Thailand's opposition Democrat Party will challenge the weekend's disputed ballot in court on Tuesday as the Election Commission probed possible campaigning irregularities and a long-running political conflict showed no sign of ending.
But in one bit of good news for caretaker Prime Minister Yingluck Shinawatra, the number of anti-government protesters, who have blocked major Bangkok intersections for weeks, appears to have dwindled.
The Democrats, who boycotted the election, will file two complaints with the Constitutional Court, spokesman Chavanond Intarakomalyasut told Reuters.
"The first regards the election directly. We will argue that the election violated the constitution, in particular article 68 which prohibits people from undermining the constitutional monarchy and trying to grab power through unconstitutional means," he said.
"In a separate petition, we will file for the dissolution of (Yingluck's) Puea Thai Party for announcing the state of emergency which meant the election could not be held under normal circumstances."
The government imposed a state of emergency last month to try to control the protests. Among other things, it allows security agencies to impose curfews, declare areas off-limits and detain suspects without charge, but it appears that such measures have not been enforced.
Sunday's election was generally peaceful, with no repeat of the chaos seen the previous day, when supporters and opponents of Yingluck clashed in north Bangkok. Whatever the result, it is unlikely to change the dysfunctional status quo in a country blighted by eight years of polarisation and turmoil.
The commission said it was looking into complaints regarding alleged abuse of authority by the government during the election.
It is due to meet on Wednesday to discuss problems surrounding the election, including the failure to register candidates in 28 electoral districts after protesters blockaded candidate registration centres in December.
MIDNIGHT AT THE OASIS
The anti-government protesters closed two camps on Monday and marched to a third, the green central oasis of Lumpini Park, but their numbers appeared to be significantly lower on Tuesday.
Small groups of people were milling around the grass after spending the night in scattered tents.
The demonstrators blocked balloting in a fifth of constituencies on Sunday, saying Yingluck must resign and make way for an appointed "people's council" to overhaul a political system they say has been exploited by her billionaire brother, former premier Thaksin Shinawatra.
The election is almost certain to return Yingluck to power and, with voting passing off peacefully across the north and northeast, Yingluck's supporters will no doubt claim a legitimate mandate.
But there was no indication of when re-runs of disrupted ballots would be held or when the commission would be able to announce a result.
Giving provisional data on Monday, it said 20.4 million people cast their vote, just under 46 percent of the 44.6 million eligible voters in 68 of 77 provinces. In the other nine provinces, no voting was possible.
Voting was disrupted in 18 percent of constituencies, 67 out of 375, the commission said, revising data given on Sunday.
The protesters say former telecoms tycoon Thaksin has subverted a fragile democracy with populist politics such as subsidies, cheap loans and healthcare to woo the poor and guarantee victory for his parties in every election since 2001.
Thaksin's critics also accuse him of disrespecting Thailand's revered monarchy, which he denies.
Thaksin has lived abroad since 2008 to avoid a jail term for a graft conviction he says was politically motivated. Critics say Yingluck is merely a stand-in for him.
Thaksin's supporters accuse the military and the establishment, including the judiciary, of colluding over the years to oust his governments.
The military, which has staged numerous coups since Thailand became a constitutional monarchy in 1932, overthrew Thaksin in 2006, but this time has stayed in the wings.
(Additional reporting by Pairat Temphairojana; Writing by Nick Macfie; Editing by Alan Raybould and Ron Popeski)