Cheryl Oates, spokeswoman for Rachel Notley, said Wednesday the premier-designate asked senior civil servants to impose the ban until the NDP assume power in the coming days.
"These are important documents and it's important that they be preserved to ensure a smooth transition into government," said Oates.
There will be a review on the rules surrounding disposal of documents to see if any improvements or tougher measures are needed, she added.
Opposition parties have been demanding action after bags and bags of shredded documents were seen being hauled away from the legislature after the Progressive Conservatives lost their 44-year hold on power in last week's election.
Government rules allow routine paperwork to be shredded, but documents that deal with ministry affairs or with information related to an access-to-information request must be saved.
There are fines for non-compliance.
Earlier Wednesday, two government watchdogs announced an investigation into accusations of illegal document shredding in the Environment Department.
Public interest commissioner Peter Hourihan and privacy commissioner Jill Clayton said the probe was based on an anonymous tip and two letters.
"Our role in the investigation will be to determine whether a wrongdoing was committed by an employee or employees," said Hourihan.
They did not provide details of what was allegedly shredded.
A spokeswoman for the Environment Department said staff will co-operate with the investigation, but will not stop shredding documents.
"There are always documents that need to be shredded in the department," said Katrina Bluetchen.
Oates said the top bureaucrat in the department has invited Clayton to visit the ministry so her concerns can be addressed.
Notley and the New Democrats are still waiting for final vote election recounts before they can be sworn in as the new government.
Premier Jim Prentice has quit politics and most of his cabinet members were defeated, but all of them still retain power as cabinet ministers until Notley is sworn in.
The Tories were reduced to third-party status in the legislature in the election following a string of controversies around the use of government planes, lavish travel and spending by former premier Alison Redford and plans for a premier's penthouse in a renovated government building.
Just before the campaign, Prentice called for an investigation into reports that the government paid out millions of dollars to a flooded-out Kananaskis golf course with ties to Tory insiders.
Opposition Wildrose Leader Brian Jean said Notley should have acted sooner when reports of mass shredding at the legislature first surfaced. He said there's concern that documentation of Tory malfeasance has been shredded.
"Here we are already a week into a new government and no steps were taken," said Jean. "I think it's inappropriate for them not to have stepped forward before now."
Alberta Party Leader Greg Clark said he will push for greater powers for Clayton and other officials to stop illegal disposal of documents.
"After 44 years is it likely the PCs have anything to hide?" Clark asked in a news release. “Where there’s smoke, there’s almost always fire.”
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