General Motors chief executive Mary Barra this week secretly met with brass from the United Auto Workers for the first time since the union called a strike last month that has idled more than 46,000 employees, The Post has learned.

In an unusual move that union officials took as a positive step, Barra on Wednesday asked UAW president Gary Jones and Terry Dittes, the union’s vice president who’s leading the main talks, to come to a conference room near her office around 3:30 p.m., two people familiar with the meeting told The Post.

Soon after, Jones and Dittes were escorted by armed guards to Barra’s office in the Detroit Renaissance office complex, where GM is headquartered, for a meeting that lasted about half an hour, the source said.

As reported by The Post, GM officials on Tuesday had abruptly pulled out of a meeting for major negotiations in which officials were slated to discuss job security and bringing jobs back to the US from Mexico.

No such meeting occurred on Wednesday either, and Barra that afternoon appeared concerned that talks were off track, according to a source.

UAW officials had been angling for a direct meeting with Barra as a way to break through on negotiations, which have remained stalled for about five days.

As reported by The Post, UAW brass last week were even discussing holding a “no confidence” vote against Barra as a way to draw her into discussions. Sources said union leadership believes it was Barra who personally decided to reverse a decision to yank health care coverage for striking workers.

During Wednesday’s surprise meeting, it’s unclear whether Barra offered or demanded any concessions, or what specific issues were discussed. Nevertheless, the meeting appears to have injected new life into the negotiations, which entered their 25th day on Thursday, sources said.

Smaller groups have continued to meet to hash out details on pension benefits, pay issues and job security, two sources said.

There’s no major meeting currently scheduled for the remainder of this week, but they have typically come together quickly after the smaller groups reach agreements on outstanding issues, the two people said.

The ongoing strike has been painful for both the company and thousands of employees who are on strike, idling 34 plants nationwide. GM’s stock has fallen more than 10 percent since the strike was called on Sept. 15. Wall Street analysts have concerns that a prolonged impasse could reduce the company’s bonds to junk status.

Workers, meanwhile, have been subsisting on $250 a week in strike pay.

UAW negotiators are primarily trying to move to the US entire lines of auto manufacturing from Mexico — which, they say, would provide more job security and create more jobs.

Talks between the company and the union took a turn for the worse over the weekend, when GM rejected a UAW proposal with more salaried and hourly workers. In a Sunday letter obtained by The Post, the UAW’s Dittes accused GM negotiators of lacking “the professional courtesy to explain” why they rejected the package.

GM submitted a new proposal Monday and is waiting to hear from UAW, according to a source close to GM.

Spokesmen for GM and the UAW declined to comment.