The Waikato District Health Board and the University of Waikato have made a joint bid to the Government to set up a school.
The University of Auckland, which has New Zealand's other medical school, labelled it an ''expensive folly'' yesterday.
Otago health sciences pro-vice-chancellor Prof Peter Crampton warned it would be disruptive and costly.
The proposed school differed because it would be graduate-entry, and training would take four years. Its backers say it would focus on attracting students from areas that need doctors, and would aim to have 60% of students specialise in general practice. The students' undergraduate degrees could be any university degree, Fairfax Media reported.
The National Party holds both Hamilton electorates.
Political commentator Matthew Hooton told the ODT the 2017 general election was unlikely to be a factor in the decision.
''I think the Government will be straight up and down on this issue, and if anything, there would be a slight political bias against Waikato University by a National Government. It's been a place that has been run by people who are strongly opposed to the National Government.
''In the end I'll think they'll call it based on a professional assessment,'' Mr Hooton said.
Hamilton East MP David Bennett is backing Waikato's bid and told the ODT New Zealand needed a third school.
''There's a need for GPs in this area and the specialist training this would provide,'' Mr Bennett said.
Prof Crampton said the current medical schools were addressing the workforce shortfalls cited in the Waikato bid. It was a worthy objective to increase doctor numbers, but it was more complicated than just setting up a school, Prof Crampton said.
Increasing trainees had a flow-on effect to the health system.
Medical education was reliant on health sector placements.
''Our health system's pretty full. It's also, to state the obvious, a fairly stressed place, with all DHBs experiencing financial pressures.''
The medical schools also had to work hard to secure placements in general practice.
''Putting 240 more medical students into that ecosystem ... would be extremely stressful and disruptive, particularly for Auckland University.''
Prof Crampton was proud of the increasing diversity of Otago medical students.
''We're graduating in the region of 45 to 48 Maori doctors this year alone. We are changing the face of the medical workforce in New Zealand.''
Prof Crampton said the National-led Government had increased medical student places by 200 per year and the increase had been successfully staggered over several years.
Establishing a new medical school was a ''massive social investment''.
Auckland University medical and health sciences dean Prof John Fraser said the plan was ''ill-conceived and unwarranted''.
''A new programme is simply not in the national interest and taxpayers will have to pay for what is an ill-considered and expensive folly.
''The existing programmes at Auckland and Otago are already meeting the needs for growth of doctors for New Zealand,'' Prof Fraser said.
Health Minister Dr Jonathan Coleman's spokeswoman said it was too soon to comment on the ''interesting proposal''. Tertiary Education Minister Steven Joyce and Dr Coleman will consider the business case proposal.
