ANZ Bank is further cutting its exposure to wealth management, selling its New Zealand life insurance business to global health insurer Cigna Corporation for $NZ700 million ($645 million).

The sale of OnePath Life, which is the latest move by ANZ to offload assets outside its core banking businesses, will help top up ANZ's already high level of capital, which is expected to be returned to shareholders through further share buybacks.

ANZ on Wednesday said it would make a $NZ50 million gain on the sale, which would slightly improve its group-wide common equity tier 1 capital ratio, by 5 basis points.

Under chief executive Shayne Elliott, ANZ has also sold off its Australian operations in life insurance, superannuation, and most of its financial advice arm, alongside various Asian retail banking assets. The strategy has been to offload lower-returning businesses and instead focus on the bank's core strengths in retail, commercial and institutional banking.

ANZ launched a $1.5 billion share buyback late last year, and it has signalled it may undertake further capital management as it accumulates capital beyond what it is required to hold by regulators.