Severance for public servants is laid out in government contracts, Treasury Board President Tony Clement said Tuesday in response to a CBC News estimate that it could cost more than $2 billion to lay off government workers in a widely expected round of budget cuts.

CBC's Greg Weston reported Monday that a worker with a year in a federal government job could get almost six months pay in severance, while someone with 29 years of service would be entitled to 82 weeks of pay in severance.

Clement says it's not surprising that people who are laid off are entitled to severance.

"This has all been collectively bargained and it’s a contractual arrangement with the union on behalf of the employees, and so we’ll meet those commitments," Clement told Rosemary Barton on CBC's Power & Politics. "We’re not going to tear up a collective agreement."

Clement says severance is borne by the department where the cuts take place, so those costs will already have been taken into account when the government tallies its total savings.

The federal public service has an attrition rate of about 11,000 a year as people retire or leave for other jobs, Clement says. The government tries to move civil servants into other jobs for which they're qualified, rather than laying them off, he says.

"It's only if he or she is disinclined to do that, or if they don’t have the skill set in any other part of government, that you get into a situation where that person will be let go," Clement said.

The federal budget is set for March 29. The government plans to cut an estimated 30,000 jobs over the next three years.