The Professional Institute of the Public Service of Canada has reached tentative deals with the federal government to replace expired contracts for 18,000 of its members — but negotiations are ongoing for more than 32,000 workers.

One agreement "has enshrined scientific integrity in collective agreements," PIPSC said in a news release on Sunday afternoon.

"Scientists will have the right to express themselves on science and their research without being designated as official spokespersons."

The agreements also include a five per cent "general economic" increase over four years, beginning in 2014 when the last contract expired, the release said.

Changes to the sick leave program, which has been a contentious issue, have not been made but a collective agreement includes "established a process to improve employee wellness and support," the release said.

"Until a new system has been agreed to at the bargaining table in the next round, the existing sick leave system remains firmly intact," the release said.

PIPSC represents scientists, auditors, information technology experts and other public service professionals.

"Our government committed to negotiate in good faith with public sector unions and to restore a culture of respect for Canada's public service," Treasury Board president Scott Brison is quoted as saying in a news release.

"I am pleased that our approach, along with the tireless work of my officials, and the leadership demonstrated by the Professional Institute of the Public Service of Canada, have produced tentative agreements that are good for our employees and fair for Canadians.

"We remain committed to reaching agreements with the rest of the public service through fair and respectful negotiations so that we can all focus on delivering on our ambitious and progressive agenda of good jobs and growth for the middle class."