Japan's second largest life insurer by premium revenue is likely to spend about ¥70 billion ($858.5 million) on the deal and is expected to reach an agreement as early as Monday, the person said.

The deal would be one of the biggest acquisitions made by a Japanese nonlife insurer targeting emerging markets.

Mitsui Sumitomo's move is the latest in a string of Japanese life and non-life insurers' overseas shopping sprees.

In recent years, major insurance companies have been aggressively looking for acquisition or investment targets to further growth, as Japan's population is shrinking and its life-insurance industry is seen as saturated.

Japan's largest life insurer, Nippon Life Insurance Co. last month agreed to buy about a 26% stake in India's Relianace Life. Dai-ichi Life Insurance Co. in December agreed to buy Tower Australia Group Ltd. for about ¥99.6 billion, making the insurer a wholly-owned unit.

Non-life insurers are even more active in overseas acquisitions. Mitsui Sumitomo Insurance bought a 30% stake in Hong Leong Assurance Bhd., the sixth-largest life insurer in Malaysia, while smaller rival Sompo Japan Insurance Inc. acquired a 94% stake in midsize Turkish firm Fiba Sigorta Anonim Sirketi for ¥28.1 billion last year.