Less than three weeks until the general election, Republican candidate for governor Jeff Johnson on Thursday secured another endorsement from a business group, the state chapter of the National Federation of Independent Business.

Johnson, who is running to unseat Gov. Mark Dayton, last month received the endorsement from the Minnesota Chamber of Commerce's political action committee.

"We're excited about his candidacy," said NFIB state director Mike Hickey. "Jeff was a very good friend of ours when he served in the legislature. He's a very impressive legislator."

Hickey also criticized the current administration for its record on issues important to the state's NFIB, which represents 13,000 small business across Minnesota, including the implementation of the Affordable Care Act in Minnesota.

"It's been a rough ride with Gov. Dayton," Hickey said.

He pointed to the Dayton's 2012 vetoes on legislation that would have reduced the commercial property tax rate and tort reform as examples of the governor's disappointing record with small businesses.

At Thursday's news conference, which came on the heels of the announcement by PreferredOne that it's insurance premiums would rise on average by 63 percent, Johnson in harsh language criticized Dayton for the MNsure and PreferredOne rate hikes.

PreferredOne sold plans with some of the lowest rates in the country but last month said it would not sell plans through MNsure in 2015. By offering the lowest rates, PreferredOne nabbed nearly 60 percent of the 55,000 Minnesotans who purchased insurance through the state exchange.

Johnson, a Hennepin County commissioner, has steadily hammered at Dayton since the Commerce Department announced earlier this month that insurance premiums for plans sold through MNsure will rise on average 4.5 percent. Republicans have called the statistic bogus, saying it masks higher rate hikes.

"That 4.5 percent statistic is bogus, it's meaningless, it's nonsense. It was a blatant lie coming from the governor," Johnson said Thursday. "I believe Gov. Dayton needs to apologize to the people of Minnesota for lying to us about the MNsure rates."

In response to accusation from Johnson that he's "lying" about the 4.5 percent rate increase for MNsure, Dayton said "Commissioner Johnson gets more desperate by the day, and so his rhetoric escalates."

On the rise in PreferredOne's insurance premiums, Dayton dismissed Johnson's claims using a baseball analogy. "PreferredOne dropped out of the system. If the Twins have a player with a lousy average and they release him, they don't include his batting average in the average of the next year's team," he said.

In the final stretch heading to the Nov. 4 election, Dayton and Johnson have stepped up their attacks on one another in debates and public appearances. They are set to debate for the fourth time Sunday.

Photo: State NFIB director Mike Hickey announced on Thursday his group's endorsement of Jeff Johnson, a Republican running against Gov. Mark Dayton. Ricardo Lopez/Star Tribune