Wednesday's throne speech left a public sector union concerned about a promise to amend the law governing the relationship between the public service and the Treasury Board.

The Conservatives once again promised to make further reductions to spending within government, and the speech reiterated changes announced in the spring about reforming sick days and performance evaluations.

But the Public Service Alliance of Canada (PSAC) said it was caught off guard by promised changes to the Public Service Labour Relations Act.

"We certainly find it pretty vague and very disappointing," said PSAC president Robyn Benson.

The act covers bargaining rights, collective bargaining, grievances, arbitration, conciliation and more.

The goal of the changes to the act, according to the speech, "is to ensure that the public service is affordable, modern and high-performing."

Robyn Benson, president of PSAC, said changing the act would be significant, especially because her union goes into collective bargaining next year.

"We're pretty surprised that it's there, and it doesn't really say what's going to happen with it," she said.

Benson said she planned to call Treasury Board president Tony Clement today to try to find out what changing the law would entail specifically.