Primary Health Care chief executive director Henry Bateman made the prediction at the company's results announcement, where executives also criticised the government's indecision over changes to Medicare which they said confused patients and created unnecessary cost for the business.

Mr Bateman, who runs Primary's medical centre network, which is one of the biggest in the country and is the son of former managing director Ed Bateman, told an analyst briefing he had got "the sense [the co-payment] is slipping off the agenda".

"The feedback that we are getting through other streams is that it won't be there come 1 July," he said. "But let's just wait and see."

Acting managing director Andrew Duff said the conduct of the government, which first proposed a universal $7 co-payment for bulk-billed general practitioner visits last May and has made major changes to the policy twice since, has been frustrating.

"It's hugely disruptive," Mr Duff told Fairfax Media after announcing a 6.2 per cent rise in half-year profit to $53.4 million. "For example the short consultation issue - that was dropped right at the last moment but we have to prepare for that and we have to spend money changing our systems."

"The main impact is on patients," he said. "Whenever there is talk, we tend to see a negative effect on volume. We would just prefer certainty rather than continual debate and change."

Prime Minister Tony Abbott dumped the $7 co-payment in December, swapping it for a $5 co-payment only for non-concessional patients, a freeze in the Medicare rebate paid to doctors and a cut in the payment for short visits. But following fierce campaigning by the doctor lobby groups new Health Minister Sussan Ley dropped the short consultation change in January.

Mr Duff and Mr Bateman were candidates for Primary's top job, but both will make way for new managing director Peter Gregg, who has worked in senior roles at Qantas and Leighton Holdings. Mr Duff said he was disappointed he did not get the top job, but would stay on as finance director.

Mr Gregg will take over from Dr Bateman, who led the company for almost three decades, at a time when investors are grappling with major changes to the way Primary accounts for acquiring doctors' practices.

The company's old accounting practices would treat upfront-payments to new doctors - in the past as much as $500,000 - as goodwill, rather than amortising them over time.

Investors have pressed for the change for some time, but despite the move the stock plunged on Wednesday. Primary shares had fell 4.7 per cent to $4.68 on Wednesday, down from a 12-month high of $5.04 almost a year ago.

The company took a $426 million non-cash write-down on its goodwill, which was welcomed by the Australian Securities and Investment Commission. "In ASIC's view, the revised accounting treatment more appropriately reflects the substance of the transactions," the corporate watchdog said in a statement.

Watermark Funds management analyst Joshua Ross, whose firm is an investor, said he supported the reporting changes and also praised Primary for picking an external candidate for lead the company. "The implication of the [accounting] changes don't change the cash flows at all so we think the share price response is an overreaction," he said.

The change to the accounting practices meant net profit for the six months ended December 31 fell short of expectations of $82.9 million among analysts surveyed by Bloomberg. Revenue rose 6.3 per cent to $798.6 million, which beat analyst forecasts of $779.3 million.

Primary chairman Rob Ferguson said he was not worried that Mr Gregg had no experience in healthcare - a sector which calls for a delicate balance between profit and care.

"Any good businessman is aware that you've got to balance the community aspect of what you're doing with the profit aspect, otherwise you're not going to be there in the long term," Mr Ferguson told Fairfax Media. "When I talked to people about him they say he's got a great strategic sense and big-picture-view of the businesses he was involved in."