Prime Minister Yingluck Shinawatra has reached out to enemies as she tries to bridge Thailand's bitter political divide, but has failed to shed her image as a "puppet" for her polarising brother Thaksin.

Yingluck, who rode to electoral victory in 2011 on a surge of support for ousted former prime minister Thaksin, is facing a flood of anti-government protesters who have vowed to topple her and rid the country of her sibling's influence.

Thaksin, who was deposed by the military in 2006, is hugely divisive in Thai politics, broadly pitting his working-class and rural northeastern supporters against the elite and Bangkok middle class.

The billionaire tycoon-turned politician lives in self-imposed exile abroad, but is widely believed to be the guiding power behind his sister, whom he once referred to as his "clone".

Yingluck has adopted a policy of strict non-violence against the protesters and has called elections to try and defuse the tensions.

Observers said this was a landmark decision in a country accustomed to violent street unrest and deadly security responses -- including the bloody military action against pro-Thaksin "Red Shirt" rallies in 2010 under a previous government.

"I am very impressed. I thought she would have cracked up any time long before this," said analyst Chris Baker.

But the premier's efforts have been derided by opposition forces which have pledged to eradicate the "Thaksin regime".

The current rallies were sparked by an outpouring of anger at an amnesty proposal by the ruling party, since quashed by the Senate, that could have allowed the return of Thaksin from exile.

The former Thai premier lives in Dubai to avoid a jail term for corruption that he claims is politically motivated.

"The problem is still the Thaksin issue himself, the man himself. If you took that out then I think everything else is relatively manageable," said Baker, who co-authored a biography of the former leader.

Observers say Yingluck has reached out to the military and establishment forces that expelled her brother and helped unseat two subsequent pro-Thaksin governments in 2008.

"She has adopted a conciliatory line. She has never lapsed into the 'tough guy' persona that has marked many of her predecessors in power," said Michael Montesano at the Institute of Southeast Asian Studies in Singapore.

"And she has endured deeply offensive, sexist attacks with unfailing grace," he added.

The former businesswoman has recently sought to play down Thaksin's influence, aware of the visceral loathing he inspires among his enemies.

But as a political novice, who was thrust into the limelight two years ago, she was initially happy to boast of her links with her brother.

"Thaksin thinks, Puea Thai does" was a key mantra of her now-ruling party as it sought to capitalise on his popularity.

"We cannot deny the fact that she has been a puppet," said former Thai diplomat Pavin Chachavalpongpun, an associate professor at the Centre for Southeast Asian Studies at Japan's Kyoto University.

But he said the ruling party won a landslide in the last election on a campaign that specifically invoked Thaksin.

"It would only make sense that Yingluck would walk into the footsteps of Thaksin. I don't think there's anything wrong, if 15 million people are supporting you," he said.

Yingluck is seen as a conduit for Thaksin-inspired policies that have proved extremely popular among voters, who have swept him or his allies to power in every election since 2001.

But analysts said those very policies have exposed inadequacies in the government, with few heavyweights able to counter Thaksin's influence.

Baker said Yingluck's political weaknesses have translated into a number of flawed policies, notably a controversial water management project and a rice scheme that is hugely popular among rural constituents in the northeast, but seen as economically damaging.

"She is a good performer but I am not sure she is a good decision-maker," he said.

Yingluck, who graduated in political science before earning a masters degree in business administration at Kentucky State University in the United States, spent much of her career working in her brother's business empire.

The 46-year-old mother-of-one began as a trainee for one of Thaksin's firms in the 1990s.

She is a former president of the mobile telephone unit of Shin Corp, the telecoms giant founded by Thaksin that was at the centre of a tax scandal over the sale of the family's shares in the group in 2006.