Insurance giant QBE expects to post a half year net loss after tax of $US750 million ($A1.1 billion), mainly reflecting the impact of COVID-19, higher catastrophe and accident claims and a loss on its investment portfolio.

The company had reported a first-half profit of $US463 million a year ago.

It said the pandemic has adversely affected multiple lines of its business, with higher claims expected due to business interruptions, health problems, higher casualties and a deterioration in credit.

This will result in an underwriting impact of around $US335 million for the six months ended June, it said. It said the combined operating ratio had blown out to 104 per cent.

In addition, the company also expects further net claims of around $US265 million to emerge over the next 12-18 months, primarily in the trade credit and lenders mortgage insurance segments.

The company said it currently estimates total COVID-19 related costs to be around $US600 million ($A848 million) on a pre-tax basis, but warned that the business landscape remains highly uncertain.

It has also suffered a net investment loss of about $US125 million, caused by “extreme investment market volatility” during the period.

“Despite the impact of COVID-19, I am encouraged by the strong underlying trends evident in the result,” group chief executive Pat Regan said.

“We are supporting customers through various initiatives including premium refunds, premium deferrals, extending credit and counselling services to vulnerable customers and accelerating claims payments,” he added.

The insurer said its debt to equity ratio is likely to be around 30 per cent as at June-end, while liquidity is expected to be around $US1.5 billion.

QBE in April raised $A1.3 billion from shareholders to build a buffer against the impacts of the coronavirus pandemic.