After the federal government announced it would overhaul the rules around sick days and disability leave in Canada's public service, unions began to quote statistics defending its employees.

On CBC Radio's Ottawa Morning Tuesday, the Public Service Alliance of Canada argued the current plan works. Employment lawyer Sharaf Sultan said the move was not a surprise and aligns with rules for other public sector workers.

Later on Tuesday, the government countered with more numbers to back up its argument.

The Treasury Board has claimed the current plan for sick days is a $5 billion liability for the government. On Tuesday, it broke down the number of sick days during the 2011-12 fiscal year for federal public servants working for the 20 largest organizations under its watch.

Among about 86 per cent of the public service, the government said workers averaged more than 17 sick days.

The chart below ranks the average number of sick days taken, paid and unpaid, by department:

Treasury Board of Canada

Department Avg. Sick days (paid and unpaid) Veterans Affairs 24.4 Human Resources and Skills Development Canada 21.8 Canada Border Services Agency 19.1 Indian Affairs and Northern Development 19.1 National Defence 18.6 Public Works and Government Services 18.6 Fisheries and Oceans 18.4 RCMP (civilian staff) 18.1 Statistics Canada 16.6 Correctional Service of Canada 16.0 National Health and Welfare 15.1 Natural Resources 15.0 Transport 14.6 Industry 14.2 Agriculture and Agri-Food 14.1 Citizenship and Immigration 13.9 Public Health Agency of Canada 13.2 Justice 13.0 Environment 12.6 Foreign Affairs and International Trade 11.5 Total average 17.4

The statistics include permanent employees, employees with terms of three months or longer and casual employees, according to the Treasury Board.

They do not include ministerial staff, census-takers, investigators, federal judges, deputy ministers, members of the Canadian Forces and RCMP, employees appointed by Governor in Council (more than 2,000 serving on more than 200 Crown corporations), employees engaged locally outside Canada and those not required to work more than one third of the normal work year.

The Public Service Alliance of Canada said combining paid and unpaid leave could be misleading, because unpaid leave was likely for long-term disability plans paid for by private insurance companies.

"It would be very interesting to have all the statistics he's using," said PSAC president Robyn Benson.

"That would be transparent, we would then know if he's mixing apples and oranges or he's talking apples and apples."

Union boycotts public service week

On Tuesday, PSAC said workers would boycott public service week, which runs from June 10-14, after Clement's announcement.

As the largest union for public sector workers, it claimed the current sick day plan does not cost the government as much as it claimed because most workers are not replaced when they are away.

PSAC also claimed the numbers are "just random averages" and they are "skewed by a small number of workers — like those in high risk and high stress workplaces such as correctional services — who need more time off."

"That number also includes workers with extended illnesses who are using up sick leave credits before qualifying for long-term disability," the union said.

Unions have not provided their own breakdown of statistics per department but they did say 95 per cent of federal workers do not use sick leave without pay.

The union also said, based on statistics they have seen, they believe federal public servants take between zero and eight days of paid sick leave per year.