The Minnesota Nurses Association on Thursday rejected the latest offer from Children’s Hospitals of Minnesota. The union also voted to authorize the negotiating team to call a strike.

Children’s made the offer June 4. Under the terms of the three-year proposal, nurses’ wages would grow 2.5 percent in the first year, another 2.25 percent in the second year, and 2 percent in the final year.

“These are higher wage increases than those the nurses received during the 2016-2019 contract, which were mutually negotiated and agreed to between MNA and Children’s in 2016,” according to the hospitals’ summary of the June 4 negotiations.

The MNA proposed a total wage increase of 12 percent over the course of the three-year contract, according to Children’s. The hospital system said that rate was “not sustainable.”

The MNA also requested for a continued freeze on insurance premiums, but union officials say Children’s turned it down.

“After all of facts and data we had presented on insurance and wages, we are very unhappy with this offer from Children’s,” members of MNA’s negotiating team wrote in a June 4 summary to workers. “This is why we need a strike vote to let them know we are serious about our prioritiesand that we will fight Children’s unfair labor practices.”

Whether MNA will proceed with the strike is unclear. According to a statement issued Thursday, the decision rests with elected nurse members on the negotiating committee. A strike could begin 10 days after MNA issues a strike warning to the hospital.

Insurance premiums and wages remain the main areas of contention between the union and Children’s, which have been negotiating since March.

“Nurses were willing to accept lower wages and benefits when Children’s was hurting from the recession,” said Elaina Hane, a pediatric intensive care unit nurse at Children’s location in St. Paul. “Now that the hospital is back on its feet, the nurses’ contract needs to catch up and prevent nurses from losing money working at the hospital.”

In Thursday’s statement, MNA officials note that the union has “made progress with the hospital on some issues.” For instance, Children’s is now offering the same workplace violence proposal that Methodist hospital offered nurses.

Bargaining was slated to resume Friday.

In another statement, Children’s officials said the strike authorization was “disappointing.”

“When you consider the progress we’ve made over several bargaining sessions and the fact that the union has declined our requests to use a mediator, it doesn’t make sense and it’s unnecessary,” said Katie Penson, senior director of clinical services with Children’s Minnesota. “Not only have we agreed to support various union priorities, like workplace safety, we have offered to go higher on wages because we value the important work that nurses do. Nonetheless, the union has chosen to focus on insurance — and has singled out one plan with the least amount of Children’s nurses enrolled.”