The market leading insurer, which is in line for a $4 billion-plus privatisation by the end of the year, has been running a trial with 26 medical centres and 145 general practitioners since late last year.

The pilot program ensures members in locations such as Brisbane, the Gold Coast, Ipswich and Cairns receive same-day appointments, fee-free consultations, after-hours GP visits and a range of one-off health assessments. Medibank pays a proportion of the administrative costs borne by the clinics, which are owned by Sonic Healthcare.

Since the trial began, Medibank members visiting the selected clinics have had out-of-pocket costs covered for 40,000 consultations.

In a speech to a healthcare industry conference on Wednesday, Medibank managing director George Savvides showed internal research that indicated 35 per cent of Medibank members were more likely to stick with the insurer on the basis that these additional services were offered.

Mr Savvides said the results so far were just "an opening of the door" that allowed Medibank to understand how it can use primary care to keep its members healthy. "Out of that comes innovation and new ideas of how we go forward to make a difference in the lives of those that we cover," he said.

Medibank is yet to decide on whether to expand the trial, but the positive reaction from members may spur the fund and its peers to push for changes to legislation that stops insurers covering the cost of out-of-hospital treatments. The trial is operating within the bounds of the law because it pays only for administrative costs, as opposed to funding the doctors directly.

Mr Savvides told the conference that insurers "need to be another funder into that space to encourage more co-ordinated and integrated care services".

His view echoed Private Healthcare Australia chief executive Michael Armitage, who recently told The Australian Financial Review that preventing insurers from covering procedures already provided for under Medicare such as GP visits was "nuts".

Changing the law would give insurers greater oversight of members' developing health problems sooner. They could suggest preventive treatment and avoid costly hospital claims.

Insurers could especially play a greater role in the care of patients described across the industry as "frequent flyers", Mr Savvides said. In Medibank's case, 2.5 per cent of its 3.8 million members account for 35 per cent of hospital claims. Of that group, 70 per cent have a chronic disease.

Mr Savvides said Medibank should know the name of each of member in that 2.5 per cent segment. "We should make their appointments [and] not let them forget them," he said. "We should send the car to pick them up and get them to the primary care service ... and do the follow-up to make sure the test got read and then the follow-up consultations occur. And then we would reduce a percentage of the unnecessary acute admissions that came from ignoring their needs."