Electronic eavesdropping devices were reportedly discovered at a former high-tech company campus in Ottawa slated to become Canada's new military headquarters, but officials said Tuesday no bugs were found.

The daily Ottawa Citizen reported that workers preparing the former Nortel complex for the Department of National Defense discovered the listening devices.

However, the newspaper added, it was not clear whether they were recently planted or left behind after industrial espionage targeting Nortel.

Broadcaster CTV, meanwhile, said the discovery has prompted the military to rethink its move from a downtown office tower complex to the campus on the outskirts of the city, due to security concerns.

Canadian Defense Minister Rob Nicholson's office told AFP, however, that security officials have assured the minister that "they have not discovered any bugs or listening devices."

"Our government continues to be vigilant when it comes to maintaining the security of information and personnel," the statement went on to say.

Last year the Wall Street Journal reported that hackers using passwords stolen from Nortel executives had downloaded technical papers, research and development reports, employee emails and other documents from the company over a 10-year period.

It cited a Nortel internal investigation, which determined the hackers were likely operating from China.

Spying software had been so deeply hidden on employee computers that it took the company years to figure out the extent of the problem.

Nortel, once Canada's largest company, filed for bankruptcy in 2009.