Decisive action must be taken to end the "dubious" practice by the Northern Ireland Civil Service (NICS) to automatically delete emails after three months, politicians and campaigners have said.
The call comes after it emerged a software system - named Trim - is in place to delete all government emails after the period of time has elapsed.
The communications are expunged unless a civil servant deems them important enough to retain, BBC Radio Ulster's Nolan Show reported yesterday.
There is no suggestion civil servants have abused the policy or system to thwart scrutiny.
The Executive Office has said the policy was in place throughout the NICS and it was reported the policy had been in place since 2009.
Maurice Frankel - who is director of the Campaign for Freedom of Information (FoI) - insisted that while the Civil Service's handling of emails is not "unique" in the UK, the public should be "sceptical" about the policy. "I think the policy needs to be reconsidered. I think deleting emails after three months on a routine basis is premature," he said.
In light of the development, the NI Information Commissioner has warned public authorities here to ensure their record-keeping practices meet legal obligations.
TUV leader Jim Allister said, in the wake of the Renewable Heating Incentive (RHI) scandal, this disclosure had once again raised issues of "transparency" at the heart of Stormont.
"Is it any wonder that the RHI Inquiry repeatedly found it difficult to get to the full truth of what happened because of important gaps in the official record when such a system was operating?" he said. "There's a fundamental issue with the people who could possibly be embarrassed by an official record making judgments as to what should be retained."
He said he has now asked the Executive to explain how departments embroiled in the scandal supplied email records to the RHI Inquiry.
UUP leader Steve Aiken said the issue urgently needs addressed, describing it as "deeply concerning and disquieting".
"If we are to take any lessons from the RHI debacle, it's that scrutiny can help prevent future scandals."
Ken Macdonald, head of regions for the Information Commissioner's Office, said: "Records can help to tell us why a decision was made, who made it and when. They are necessary to create confidence in any decision making process, to promote accountability and transparency."
An Executive Office spokesperson said it was "simply wrong to say" emails were automatically deleted after three months.
"Emails deleted from work inboxes can be retrieved within a certain period of time, if there is a business reason to do so, but it is costly to do so and is only carried out in very exceptional circumstances."
They also said it is standard practice to save or delete information according to policy, meaning "that emails should be retained if they have long-term administrative or historical value; contain information, advice or explanation not duplicated elsewhere; relate to decisions or action taken and has evidential value; form a significant".