HONG KONG (Reuters) - Five insurers including Metlife Inc (>> Metlife Inc) and AIA Group Ltd (>> AIA Group Ltd) have submitted final bids to have their products distributed by Citigroup (>> Citigroup Inc) in Asia, a deal estimated to generate more than $10 billion (£6,115,833,893) in revenue over 15 years, people familiar with the matter told Reuters.

British insurer Prudential Plc (>> Prudential plc), Canada's Manulife Financial Corp (>> Manulife Financial Corp.) and Hong Kong tycoon Richard Li's insurance company FWD Group are the other companies that have submitted final bids, they said.

Global insurers are increasingly relying on bank distribution to ramp up insurance sales in Asia, where rises in personal incomes for many countries have enabled individuals and families to afford insurance.

If successful, the Citigroup deal would be Asia's second-biggest bancassurance deal behind Prudential Plc's (>> Prudential plc) agreement with Standard Chartered Plc (>> Standard Chartered PLC), people familiar with the matter said.

There will most likely be just one successful bidder, although there is an outside chance that Citigroup may pick two given that the deal covers 14 Asian markets, one person said.

FWD has only bid for bancassurance in four markets, while rest of the suitors are seeking Citigroup's partnership in most of the 14 markets, they said.

All the bids have come in around the same value, and suitors have improved their offers from the preliminary round, underscoring the strong interest in the sale process, a person said, adding that a deal should come early next year.

The estimated $10 billion in future sales would be split between the winning insurer and Citigroup, and the deal also includes an exclusivity payment of $1.5-2 billion by the insurer to Citigroup, the people added.

A Citigroup spokesman declined to comment, as did representatives for the five insurance companies. Sources declined to be identified as the discussions are private.

A successful bid would give that firm access to Citigroup's 600 branches and over 34 million retail accounts in the region where the Wall Street bank has about $218 billion under management, including the assets of its private bank.

Last year, Citigroup's Asian consumer bank business accounted for about half of the $15 billion generated by Citigroup Asian unit.

Bancassurance, as these agreements are called, was virtually non-existent in Asia but it has taken off since early 2000 and now accounts for 40 percent of insurance sales in Indonesia and half of all sales in Hong Kong. Still, it lags the sales in developed markets such as Spain, where 60 percent of all insurance sales come from bancassurance.

Bancassurance has been a central plank of the roughly $32 billion insurance industry M&A struck in Asia-Pacific region in the past two years. That includes Sun Life Financial Inc's (>> Sun Life Financial Inc.) and Malaysian state investor Khazanah's deal to buy Aviva Plc's (>> Aviva plc) Malaysian insurance joint venture with lender CIMB Group (>> CIMB Group Holdings Bhd) for $597 million earlier this year.

(Reporting by Denny Thomas; Editing by Edwina Gibbs)

By Denny Thomas