Life insurance industry net profit plummeted more than 24% in the year to September 30, according to latest figures from the Australian Prudential Regulation Authority.

The decrease to $1.8 billion came as total revenue increased 25.4% to $39.6 billion.

Most of the revenue gain came from investments, which increased by $5.3 billion to $12.3 billion.

Total expenses jumped 29.1% to $36.2 billion, and net policy liabilities grew to $16.3 billion from $10 billion.

Individual disability income profit was $275.7 million in the red over the year, with $172.9 million lost last quarter.

Individual lump sum was the best-performing product line, recording $88.5 million in profit, while group lump sum risk made $7.2 million profit and group disability $7.3 million.

Profit fell across all four product lines in the September quarter.