LONDON (Reuters) - Former Thai prime minister Thaksin Shinawatra is in talks to buy the Bakrie family's 23.8 per cent stake in Indonesia-focused coal miner Bumi, a report on Sunday said.

The price Thaksin, who was ousted by the army in 2006, would be willing to pay is unclear, The Sunday Times reported, adding that he had hired UBS.

Bumi was co-founded by financier Nat Rothschild and the Bakrie family, but has struggled in the past two years to overcome bitter boardroom battles, a probe into financial irregularities and the tumbling price of coal.

Bumi and the Bakrie family are now seeking to part ways and last year the Bakries agreed to exchange US$278 million (S$356 million) in cash and their shares in London-listed Bumi for the group's minority holding in Bumi Resources, but the length of negotiations has raised questions over the family's ability to come up with the cash.

The Sunday Times said that Thaksin's arrival will raise fears that Bumi's deal with the Bakries is now dead and that investors will worry that any deal with Thaksin could be on less attractive terms.

Bumi and Thaksin declined to comment on the story, while the Bakries could not immediately be reached for comment.

Bumi's chief executive Nick Von Schirnding said in June that Bumi had received guarantees that the outstanding US$228 million the company is owed by the Bakries to finalise the deal was available.