A report issued on Thursday by Canada's budget watchdog has shown that the government and taxpayers have spent paying $871 million to sickly public servants in 2011-2012. The Public Service Alliance (PSAC) of Canada, meantime, said it will thwart attempts to cut full-time workers' allowable paid sick leaves of 15 days a year.

The Parliamentary Budget Office, in its report, said it found that the 33 per cent increase in spending on the sick leaves of public servants compared with the $519 million spent in 2001-02 were due to a growth in the number of paid sick days used, 25 per cent due to improved wages, 25 per cent due to a higher population in the public service and 17 per cent due to unnamed other factors.

On average, federal public servants in core public administration took 11.52 paid sick days a year in 2011-12, according to the report by the country's budget watchdog.

The PSAC is currently in a clash with Treasury Board President Tony Clement over the latter's claims that the average federal public servant takes about 18 days a year in sick leave.

The Treasury Board and PSAC's 27 bargaining units are debating over the allowed number of payable sick leaves.

"We're not in a race to the bottom, and we're not in concession bargaining. We're not prepared to give up our sick leave," Robyn Benson, national president of PSAC, said in thespec.com.

"We have time and time again said that Mr Clement is incorrect. Our members do not abuse sick leave . . . . Mr Clement has said we use upwards of 18 days a year when we only actually earn 15."

He said government had always been fast in issuing and declaring numbers and figures but when asked to detail, "they don't have an answer for us."

"And we asked the question, and will continue to ask the question, what's wrong with our sick leave benefits now?"

But Mr Clement it seemed will push through with any sick leave days reduction plans.

"I am committed to going into the negotiations to change this antiquated 70-year old sick-leave system, to make sure that taxpayers are protected and get better results from our employees," he said on Thursday.

"There are better systems out there in both the private sector and the public sector that can institute a short-term disability term that does not involve these banked sick days . . . and at the same time provides the level of coverage that is necessary to ensure that people who are genuinely sick get the help they need," Mr Clement said.