Commonwealth Bank of Australia (CBA) subsidiary CommInsure has increased general insurance written premium by almost a third in the year to June 30 despite the challenging trading environment.

The division's cash net profit lifted 36% to $116 million in the year to June 30 as a result of new business growth, although underlying profit dipped 4% to $128 million.

The insurer recorded 29% growth in general insurance premiums while life premiums increased by 17%.

Overall, CBA group premiums climbed 25% to $1.56 billion compared to $1.25 billion in 2007/08.

The wealth management division that houses CommInsure didn't have such a happy year, reporting a 35% fall in underlying net profit of $514 million as a result of investment impairments and unrealised mark to market losses from widening credit spreads.