Canada's information commissioner reported last month finding evidence of "systemic interference" with access to information requests by three Conservative staff members who worked for Christian Paradis when he held the Public Works portfolio.
But his replacement, Diane Finley, has suggested that sending the matter to the police would be a waste of resources.
New Democrat MP Charlie Angus says he'll ask a Commons committee to call Finley to appear this week to explain her decision.
Information Commissioner Suzanne Legault's report followed an investigation into cases that date back to 2009 in Paradis' office.
She had already found against one staff member, Sebastien Togneri, in a previous investigation sparked by a Canadian Press access to information request.
Togneri resigned in 2010 after The Canadian Press reported he had been involved in other cases of meddling. The names of colleagues Marc Toupin and Jillian Andrews also appeared in emails tabled with a parliamentary committee.