Just two bidders are now vying for the stake in the mid-sized lender which is controlled by Standard Chartered and PT Astra International, who each own a 45% stake, Purnomo told reporters.

"Permata is finalising (the bidding process). It now depends on the shareholders to choose," he said, adding that Sumitomo Mitsui Banking Corp (SMBC), an arm of Japan's Sumitomo Mitsui Financial Group (SMFG), was the most serious bidder.

Purnomo did not give details of the other bidder.

Takeover interest in Permata gained ground this year after StanChart said in February its investment in the bank was no longer core.

Sources have previously said a controlling stake in the bank, which is valued at about $2.4 billion, is up for sale.

SMFG's chances of snapping up the Permata stake improved after two key rivals dropped out of the race for the lender, sources said earlier this month.

Its SMBC unit currently operates in Indonesia through its subsidiary Bank BTPN.

Japanese banks have been keen investors in overseas markets, particularly in Asia, as they struggle with prolonged low interest rates at home and a shrinking population.

Indonesian regulators, meanwhile, have been trying to encourage the 100-plus banks operating in the country to consolidate.

Asked whether the OJK, which has to approve the deal, has requirements for the stake sale, Purmono said he expected any buyer to "create value add and commit to pushing for more investment, infrastructure and small-, medium-sized businesses financing."

(Reporting by Maikel Jefriando; Writing by Fransiska Nangoy; Editing by Richard Pullin)