The Finance Minister says the costs involved in building a new medical school at Waikato University have been through a thorough business case.

Construction will begin this year - with the school providing 120 doctor training places a year, focused on primary care and rural health.

The Government's chipping in $83 million dollars, and the university and philanthropic investors will contribute $150 million.

When asked what would happen if the others can't come up with the money, Nicola Willis was clear.

"I'm going to say - well, you said you would, so you're in trouble now and you're going to have to find the money."

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