ROCHESTER — The financing plan for a massive expansion of Mayo Clinic needs a small change from state legislators, which is making some lawmakers worried that politics could cause a delay.

A state law outlines how the Mayo Clinic’s 20-year plan to remake its flagship campus, the Destination Medical Center, will be funded, including $327 million in state aid. But that aid is contingent on $6 billion in private investments, and the Minnesota Attorney General’s office issued an opinion saying those investments need to be doubled in order to tap state money.

Local officials in Rochester said the law’s unclear language is creating problems for their upcoming budget, and Republican Sen. Carla Nelson of Rochester is concerned investors will back out.

It’s up to state lawmakers to make an adjustment, but tax bills usually become overly complicated, said Rep. Greg Davids, who will lead the House Tax Committee in 2015.

“Anytime you bring a bill on the House floor that has to do with taxes, it could become a Christmas tree,” the Preston Republican said. “You could have more lights and bells and whistles put on that tree than you could imagine.

“If I get on the House floor and there’s amendment after amendment after amendment to get political, I’ll just pull it back. Then it’s not quite so simple, is it?”

The money for the project is on hold until the city is reassured the state aid will come through, Assistant City Administrator Gary Neumann said.

The city plans to write and approve the project’s budget in December, then amend it to include more project funding after the Legislature makes a fix. Davids said he plans to hold hearings on the issue next year, and Nelson said lawmakers must make “a swift, clean fix or correction to the technical language about the (Destination Medical Center).”

The development plan for the Destination Medical Center is expected to move forward in the next few months.