BANGKOK: Thai Prime Minister Srettha Thavisin discussed overcoming political divisions on Thursday with the predecessor who ousted his party's last government, as he prepares to pick a cabinet from a crowded 11-party alliance that includes fierce rivals.

Srettha sailed through a parliamentary vote to become premier on Tuesday and will head a tricky coalition that includes parties backed by a royalist military that has repeatedly manoeuvred against his Pheu Thai Party.

His meeting with the outgoing premier and former army chief Prayuth Chan-ocha underscores a fragile detente in Thai politics, with Prayuth the architect of a 2014 coup against the last Pheu Thai government. Prayuth stayed in charge for nine years.

"Existing divisions will be difficult to overcome. One conversation will not finish it off. It will take time," said Srettha, wearing a yellow necktie, the colour associated with the monarchy.

"I understand his intentions, that he wants to overcome divisions and he cares about the country."

Asked by reporters what advice Prayuth gave, he said "for me to be calm, be patient and protect the nation and monarchy."

Real estate tycoon Srettha was thrust into politics just a few months ago and has no experience in government.

TESTY RELATIONSHIPS

Speculation has been rife that his surprisingly smooth ascent to the top job is part of a secret deal between warring elites in Thailand that included Tuesday's dramatic homecoming of Pheu Thai's billionaire figurehead, Thaksin Shinawatra, after 15 years in self-exile.

Thaksin, 74, was hospitalised with high blood pressure on his first night in prison, where he is serving an eight-year sentence for abuse of power and conflicts of interest.

Thaksin and Pheu Thai have denied the existence of a deal with their rivals in the military and conservative establishment.

Prayuth, who has a testy relationship with the Shinawatra family, told Srettha healing rifts was important.

"The country must move on and the new government should look into this," Prayuth told reporters.

Srettha has the difficult task of forming and holding together a potentially fragile coalition that includes rival camps with a history of betrayal, raising the prospect of internal challenges that could complicate policymaking.

Thailand has gone through two decades of on-off political instability including two coups and intermittent bouts of street demonstrations, broadly pitting the Shinawatras and their business allies against conservatives and old money families.

The media has also been speculating about who will get the key cabinet posts, some suggesting Srettha himself would take on the additional role of finance minister.

The new government will then have to deliver their policy objectives to a joint session of parliament before they can start work in late September.

The new administration faces the crucial task of reviving Southeast Asia's second-largest economy, which the central bank forecast will grow at just under 3.6% this year.