Anti-government protesters blocked voting Sunday in dozens of constituencies in a Thai election that was overshadowed by pre-poll bloodshed, an opposition boycott and fears of protracted political limbo.

Despite weeks of mass street demonstrations aimed at forcing her from office, Prime Minister Yingluck Shinawatra was widely expected to extend her billionaire family's decade-long winning streak at the ballot box.

But few expect the controversial polls to end the cycle of political violence that has plagued the kingdom since her elder brother Thaksin Shinawatra was ousted as premier by royalist generals in 2006.

Tensions were running high after a dramatic gun battle between rival protesters on the streets of the capital on the eve of the election that left at least seven people wounded.

But there were no reports of serious violence on election day by the time polls closed at 3 pm (0800 GMT).

Officials said voting was disrupted in parts or all of 127 out of 375 constituencies nationwide because of the demonstrators, who want Yingluck to step down and make way for an unelected "people's council" to oversee reforms to tackle corruption and alleged vote-buying.

In many parts of the south, a stronghold of the anti-government movement, demonstrators stopped post offices from distributing ballot sheets and boxes, the Election Commission said.

Sunai Phasuk, a senior researcher with New York-based Human Rights Watch, accused protesters of using "thuggery and intimidation".

In Bangkok, 488 out of 6,673 polling stations either could not open, or closed early, because of a blockade by protesters or a lack of staff, sparking minor scuffles between would-be voters and police in one district.

"I just want to vote," said Praneet Tabtimtong, 57, clutching a large wooden club.

"They closed and did not bring the ballot boxes out," she added.

But in the government's heartland in north and northeast Thailand, as well as some areas of the capital, voting went ahead without major disruption in a boost to Yingluck's hopes of re-election.

"I did my duty today as I came to vote -- it's my right," said Pui, 43, who cast his ballot at a polling station in the city's historic district where a handful of police watched over voters.

'Thailand cannot afford more casualties'

Authorities said roughly 130,000 police were deployed around the country for the vote, but with tens of thousands of polling stations many had only a light security presence.

At least 10 people have been killed and hundreds injured in clashes, grenade attacks and drive-by shootings since the opposition rallies began, with victims on both sides.

"It is very, very important for leaders of both sides to completely reject violence," said Sunai. "We cannot afford more casualties in Thailand."

The backdrop to the unrest is a long-running political struggle pitting Thailand's royalist establishment -- backed by the courts and the military -- against Thaksin, a billionaire tycoon-turned-politician who lives in Dubai to avoid a prison term for graft.

Yingluck's opponents say she is a puppet for her brother, a hugely controversial figure who is both adored and hated in the deeply divided nation.

The protests were initially triggered by a failed amnesty bill that could have allowed Thaksin to return without going to jail.

The recent violence is the worst political bloodshed in the kingdom since 2010 when protests by pro-Thaksin "Red Shirts" left more than 90 dead and nearly 1,900 injured in clashes and a military crackdown.

The elite-backed opposition Democrat Party -- which has not won an elected majority in around two decades -- refused to take part in the vote, throwing its support behind the anti-government protests.

Disruption by demonstrators to candidate registrations means that if Yingluck wins she will still remain in a caretaker role with limited power over government policy until by-elections are held to ensure there are enough MPs to convene parliament.

Election officials have warned that the result may not be known for months and there were no exit polls. The opposition is also expected to ask the courts to annul the outcome based on legal technicalities.

"When the election is nullified we will confiscate Yingluck's assets and get back money that was spent on the election," protest leader Suthep Thaugsuban told supporters Sunday.

The government has been reluctant to use force against the demonstrators, despite declaring a state of emergency last month in the capital and surrounding areas.