Kevin Page, the Parliamentary Budget Officer, set the end of business hours on Friday as the final deadline for government departments to report the savings and reduction measures contained in the last budget.
On Sunday, after six months of requesting this information, Page confirmed his office "will be filing and serving legal notice on all non-compliant Deputy Heads early this week."
"As it is now clear that this matter will constitute the subject of a legal action, it would be inappropriate for me to comment further," Page said in a written statement to CBC News.
As of Oct. 16, only 19 departments out of 82 had complied with the PBO's request.
Officials in 43 departments had promised to comply and were given until Friday to do so while 20 had yet to respond altogether, including officials at the Canadian Food Inspection Agency, Citizenship and Immigration, Environment, Finance, Foreign Affairs, International Trade, Justice, Treasury Board and Veterans Affairs offices.
As CBC News reported on Friday, Page's office said it had received "only one information package from a small federal organization" by 5 p.m.
Feds spar with PBO
"We have always provided information to the PBO that falls within his mandate and we will continue to so," said Andrea Mandel-Campbell, spokesperson for Treasury Board President Tony Clement in a written statement to CBC News on Sunday.
In recent weeks, what falls within the PBO's mandate has become the subject of debate among cabinet ministers who have made clear they believe the federal budget watchdog is overstepping his mandate.
The mandate of the parliamentary budget officer as stated in the Parliament of Canada Act is to "provide independent analysis to Parliament on the state of the nation's finances, the government's estimates and trends in the Canadian economy."
But on Friday, Finance Minister Jim Flaherty told CBC News Network's Power & Politics the information Page is requesting is not part of his mandate.
"He's asking for information about money that's not spent, which is a very odd thing for the parliamentary budget officer to ask," Flaherty told Power & Politics guest host Hannah Thibedeau. "His mandate is to review government spending, not to review spending that was reduced."
Flaherty's comments mirrored those made by Clement on CBC Radio's The House on Oct.6 when he said "I'm making the argument that he [Page] is outside his mandate. There's lots of work for him to do inside his mandate and he should stick to that."
Clement told the host of CBC Radio's The House Evan Solomon that the federal government was prepared to defend that position in court, if need be.