The Government says there is growing evidence doctors' profits are rising ahead of inflation.
Health Minister David Cunliffe has promised to keep a close eye on fee rises by family doctors, and other changes, in order to keep such costs down.
Mr Cunliffe said in a speech on Friday that Labour's core primary health care reforms are delivering and gaining bipartisan support.
But he said most care is still delivered by general practitioners, and there is a lack of integration with maternity, pharmacy, physiotherapy, laboratory and other services, including hospitals.
He also says there are still too many practices that derive half or more of their income from patient co-payments, and despite the fees review process, these are rising.
But Mr Cunliffe says fees review alone cannot fully constrain costs, and incentives to keep cost increases down must be built into primary healthcare funding systems.
General practitioners say Friday's announcement is what they have been asking for, for years.
The Independent Practitioners Association Council and the Medical Association both say it is past time for Primary Health Organisations to become true multidiscplinary bodies.
They say there should be funding for services such as midwifery and physiotherapy, and not just for general practice.
