The cost of insurance on the MNsure health exchange is on the rise, state officials said Wednesday, though premium rates in the Twin Cities will remain lower than in many parts of the country.

The average premium increase for companies continuing to offer policies on MNsure next year will be 4.5 percent, according to numbers released Wednesday by the state Commerce Department.

But the absence in 2015 of low-cost provider PreferredOne, which recently pulled out of the market, likely means bigger increases for many shoppers.

For example, a 25-year-old in the Twin Cities could get a "bronze" policy from Pre­ferredOne for $91 per month this year, but the cheapest option next year jumps to $110.

The new numbers provided fresh ammunition to supporters and critics of the MNsure exchange, with the two sides interpreting the data in sharply different ways.

Gov. Mark Dayton, who joined other Democrats in pushing to create MNsure in 2013, said the numbers show "a small increase in the rates overall."

But Senate Minority Leader David Hann, R-Eden Prairie, called the 4.5 percent figure "deceptive" and "completely bogus," saying the cheapest options for many consumers will be 18 percent to 37 percent higher than they are now.

"The average amount of increase the consumer will pay … will be much higher than 4.5 percent," Hann said.

Minnesota launched the exchange as part of its implementation of the federal Affordable Care Act, which requires almost all Americans to have coverage or pay a tax penalty.

Even with the premium increases for 2015, the cost of a mid-level benchmark policy on MNsure for a 40-year-old will be about $182 per month, state officials said. That's less than the rate for comparable plans in 16 other metropolitan areas, according to figures published in September by the Kaiser Family Foundation, which is based in California.

On Wednesday, the Commerce Department supplemented the foundation's analysis with preliminary and current rates from more than two dozen other metropolitan areas, and concluded that rates in the Twin Cities are the lowest.

"When you compare Minneapolis and St. Paul to every metropolitan region throughout the country, Minnesota has the lowest rates in the nation," Commerce Commissioner Mike Rothman said during a news conference near the State Capitol.

Scott Leitz, MNsure's chief executive, said many consumers who face premium increases likely will qualify for tax credits to help offset the costs. Last year, low rates in the Twin Cities meant that many consumers were surprised when they did not qualify for tax credits.

Technology problems with the MNsure website as well as an overwhelmed call center frustrated thousands of Minnesotans who tried to use the exchange last year. The next open enrollment period starts Nov. 15, and Leitz predicted that the "consumer experience for Minnesotans will be improved."

Before Wednesday's announcement, health insurance experts pointed to several factors that likely would drive premium increases. MNsure will withhold a larger share of premiums next year to cover the cost of the exchange. Health costs are growing, in general, and more patients with costly health problems likely will move from a state safety net program to MNsure.

While the rate release Wednesday provides consumers with their most detailed information yet about 2015 health insurance costs, it doesn't answer all questions. The Commerce Department, for example, isn't releasing information about premiums for policies sold in the traditional market "outside" the exchange, which is where PreferredOne customers would need to shop if they want to stick with the health plan.

By early September, 54,510 Minnesotans had purchased commercial coverage through MNsure, with nearly 60 percent selecting PreferredOne.

Rothman, the Commerce commissioner, said his department will help consumers with the disruption caused by PreferredOne leaving the market. Dayton said he would like to see options remain as inexpensive as possible, but added: "If the low-cost options are not financially viable for the company to provide anymore, then that's the reality you get in the marketplace."

The 4.5 percent overall increase in premiums is an average that isn't weighted for membership among the four returning insurance companies.

The average premium increase at Eagan-based Blue Cross and Blue Shield of Minnesota will be about 17 percent for the company's 9,900 customers who enrolled through MNsure. Those customers account for about 22 percent of all commercial enrollees through the exchange, said Blue Cross spokesman Jim McManus.

Minnetonka-based Medica, which has about 2,000 customers through MNsure, is increasing rates on average by 1.8 percent.

At Minneapolis-based UCare, customers will see an average decrease in premiums of about 9 percent. Currently, fewer than 600 people have enrolled in UCare policies through MNsure.

Commerce put the average premium increase for Health Partners at about 8.1 percent. But a spokesman for the Bloomington company, which insures about 5,000 MNsure customers, said he wasn't sure how Commerce arrived at that figure.

Christopher Snowbeck • 612-673-4744