CONCORD, N.H. – A lawsuit will be filed against New Hampshire next week contesting the state’s reduced contribution to the state pension fund for municipal employees, one of the lead plaintiffs said Friday.

Communities and school districts expect to pay roughly $27 million more in contributions over two years.

The Legislature temporarily reduced the state’s share for municipal employees from 35 percent to 30 percent this year and to 25 percent next year.

The suit argues the state’s reduced contribution rate violates the constitution’s prohibition against mandating costs onto communities without their consent. Gov. John Lynch and lawmakers reduced the contribution to help balance the state budget. The law calls for the state to return to paying 35 percent in 2012.