Connecticut mayors grappling with rising retirement costs and sinking economies this week issued a distress signal to lawmakers in Hartford: Save us from our public unions.

The state would be in a “stronger position if we don’t negotiate for benefits,” Joe DeLong, the executive director of the Connecticut Conference of Municipalities, told a committee convened by the legislature to restore fiscal stability and economic growth. The conference of municipalities implored the state to end collective-bargaining for pensions and health-care benefits as well as limit binding arbitration when unions and local politicians deadlock during contract negotiations. This usually results in a sweet deal for the unions.

“We’re suggesting it’s very difficult in the state of Connecticut under the current labor agreements and under binding arbitration,” said Waterbury mayor Neil O’Leary, a Democrat. His town’s health care and pension costs make up 30% of its budget.

Gov. Dannel Malloy, after multiple tax increases, last year tried to close the state’s $3.5 billion deficit by shifting teacher pension costs to municipalities. Mayors warned that this would lead to property tax hikes. The legislature punted some pension payments to the future, but mayors are worried that they will eventually be required to pick up more of the bill.

That’s because state lawmakers have little flexibility to cut spending since Mr. Malloy extended collective-bargaining agreements through 2027 despite receiving few concessions from government unions. Meanwhile, tax revenues have been declining amid a sluggish economy and retirement costs are soaring. About 35% of state revenues go to debt service and retirement obligations. Connecticut’s annual teacher pension contribution is projected to quadruple by 2032.