A consumer watchdog has rebuked private health insurers for confusing people with vague or conflicting information on benefits, especially public hospital cover, as complaints hit a 12-year high.

On Tuesday, the Private Health Insurance Ombudsman said it had received 1219 complaints between April and June this year, a 30 per cent rise on the same period last year and the highest number since 2003.

Nearly 30 per cent of complaints to the PHIO in the second quarter were about market leader Medibank Private. Credit:Reuters

While routine hikes in premiums and end-of-financial-year deadlines usually drive a spike in complaints in the second quarter, the ombudsman said frustration over benefits and membership issues caused the increase.

It chastised health insurers such as Medibank and Bupa for a lack of clarity surrounding public hospital-only cover, saying too many customers were being led to believe they could avoid a public hospital waiting list.