The other bidder left in the race is rival Singaporean lender Oversea-Chinese Banking Corp, the sources added. However, they cautioned that no final deal has been agreed and there could be last minute changes.

"This is a race between DBS and OCBC," said one of the sources.

Singapore's banks have been expanding in wealth management, picking up assets sold by some Western banks as they retreat to focus on their own markets.

A win for DBS would help strengthen its lead in wealth management among Singapore's three listed banks, while a victory for OCBC would enable it to overtake DBS.

The sale is part of a restructuring by Barclays' new chief executive, Jes Staley, and comes as several European banks rethink their Asian strategy due to pressure at home to cut costs.

DBS, OCBC and Barclays declined to comment.

Buyers of Barclays' Singapore and Hong Kong subsidiaries would gain access to $20 billion worth of private client assets, sources have said previously.

Julius Baer and United Overseas Bank also took part in the initial stages of the sale process, they said. Spokespeople for Julius Baer and UOB declined to comment.

OCBC's private banking arm, Bank of Singapore, had $68 billion worth of assets under management at the end of 2015, whereas DBS private bank had S$97 billion (£49 billion) of assets belonging to high net worth clients.

Unlike DBS and OCBC, UOB has not pursued acquisitions to expand its private bank, leaving it smaller than those of its two rivals.

(Reporting by Saeed Azhar and Anshuman Daga; Editing by Denny Thomas, Greg Mahlich)

By Saeed Azhar and Anshuman Daga