TORONTO -- Auditors are investigating five Ontario government ministries after staff at the Ministry of the Environment and Climate Change altered dates on freedom of information requests to improve their compliance statistics.

Information and Privacy Commissioner Brian Beamish said Monday that there were concerns with the accuracy of the compliance statistics submitted by the ministry for his annual report in 2015.

Senior management became aware last June that staff in the ministry's Corporate and FOI Services office were deliberately changing the dates recorded in the FOI tracking system and ordered an internal audit, added Beamish.

"Auditors have concluded that the dates in the ministry's request tracking system were systematically adjusted by staff in the FOI office in order to show completion of requests within the 30-day requirement," he said in a statement. "In other words, dates were changed to improve the ministry's compliance statistics."

Falsifying statistics is a serious issue that can erode the trust and confidence of people who should be able to rely on their accuracy, said Beamish.

"The public's right to access government-held information forms an important part of a democracy and reflects an open and transparent government," he said. "Ontarians expect, and deserve to know that these duties are being carried out in an open and ethical manner."

The commissioner said he remained "deeply concerned" about the fact staff altered the dates, but added he was satisfied the issue was "addressed swiftly and thoughtfully" by the ministry.

"I am also pleased that the government intends, at my request, to conduct audits of five other ministries in order to determine whether the issues that arose in this ministry are more widespread," Beamish said.

"My office will continue to work with the Ministry of the Environment and Climate Change, and the broader Ontario Public Service, to provide guidance and support as they ensure their compliance with Ontario's access laws."

The Progressive Conservatives said it was "startling" to hear ministry staff deliberately altered dates on FOI requests.

"People are tired of this government," said PC environment critic Lisa Thompson. "They can't trust it, and Premier Wynne and her cabinet are giving us more and more reasons each day not to have faith in them."

Environment and Climate Change Minister Glen Murray must accept responsibility "for this blatant attempt to cover up poor performance" to ensure this type of "unethical" violation doesn't happen again, added Thompson.