The proposed deal, if confirmed, would be the biggest acquisition by a Japanese insurer.

As part of the deal, Dai-ichi Life is seeking to buy all shares in Protective following the approval by the US insurer’s board.

According to Japan’s Nikkei business daily, Dai-ichi is planning to enter into final talks with Protective early next week and the deal is expected to close on the same week.

The media reported that Dai-ichi was prepared to pay about JPY500bn or ($4.9 billion) for the deal.

Dai-ichi said: "It is true that we are looking into purchasing a U.S. life insurance company, it is not true that we have made a decision at this time."

"The company will promptly and formally announce matters, if any, that require disclosure," the statement added.

Dai-ichi is looking to broaden its overseas business beyond Asia by entering the world’s biggest market for insurance sold to consumers, the Nikkei said.