Exasperated Canadian air safety officials on Thursday told passengers "to leave their water pistols and toy guns at home" because they were triggering big delays at airport security.

Screening staff found nearly 3,000 toy guns, water pistols, toy grenades and other items resembling real weapons between January and June of this year, the Canadian Air Transport Security Authority said.

"Through an X-ray machine, those items look like a threatening object. We cannot take any chances," said the authority's Kevin McGarr.

"Canadian travellers have to know what they can and cannot bring on board an aircraft. The consequence is a stressful wait for other passengers and a misuse of resources meant for a real emergency," he added in a statement.

Last year, the interception of prohibited items at Canadian airport security checkpoints caused delays totaling 15,000 hours, the authority said.