ST. PAUL — A wave of Rochester residents is descending on the Minnesota Capitol for an annual lobby day that takes on extra importance this year.

Rochester officials are aiding the Mayo Clinic in its push for state help toward a multi-billion dollar expansion. Last week, Mayo leaders said they were counting on a tax diversion worth more than $500 million to pay for anticipated public infrastructure needs.

The actual bill to authorize the future subsidy hasn’t been introduced. Democratic legislative leaders say it will require extensive scrutiny because the financing plan could set a precedent.

The chamber of commerce-sponsored “Rochester On Tour” event culminates with an evening reception that lawmakers are being encouraged to attend.

This is the 10th year Rochester has organized a mass lobbying day at the Capitol.