The union representing licensed professionals in British Columbia says its latest escalation of strike action could result in "costly delays" in projects such as the expansion of the high-profile Red Chris mine. 

Professional Employees Association executive director Melissa Moroz says engineers, geoscientists and mining inspectors are among those now on the picket lines as all but its essential members take strike action. 

Moroz says those professionals support projects such as the Red Chris copper and gold mine in northwestern B.C., one of five national-interest projects that was identified to fast-track by Prime Minister Mark Carney for its potential to strengthen Canada’s role as a reliable supplier of copper.

She says their strike will present a "problem" for the mine's expansion. 

The union has been striking alongside thousands of members of the BC General Employees' Union, with more than 1,600 professionals now off the job in the latest escalation.

The BCGEU announced its own escalation Thursday, adding 370 workers to picket lines, and with 25,000 of its members strike, union president Paul Finch says that's a "near-full walkout." 

The Canadian Federation of Independent Business says the BCGEU strike has led to weakened confidence by small businesses in the province.

The federation's October survey shows B.C. businesses expect poorer performances in the months ahead, second-lowest in the country after Alberta. 

The federation says restaurants and bars have been especially hard hit with the shutdown of B.C.'s provincial liquor distribution network, and the group is calling for the province to resolve the strike and improve access to private supply.

Moroz says talks between the PEA and the province broke off earlier this week after government did not improve its offer, and the union had no choice but to step up the pressure. 

"I hope that our escalation shows government that our members are serious," she said during an announcement of the latest job action on Thursday. "We've never had this kind of strike before. We're hoping the employer takes note and comes back to the bargaining table and makes a reasonable offer so that we can get a deal."

Professionals with the union are employed across several provincial ministries including Health, Attorney General, Mining and Water, Land and Resource Stewardship.

The union said talks broke down Tuesday when government negotiators didn't increase a wage offer of 3.5 per cent over two years.