Ceramic knives from supermarket chain Aldi – which were thought to potentially pass undetected through metal screening – have been given the all-clear by Police.

Airports, government buildings, ports and nightclubs rely on metal screening to keep dangerous weapons out, but the weapons must be detectable to be found.

The Gold Coast Bulletin demonstrated that the 15cm ceramic knives, which stay sharper for longer than metal equivalents, could not be detected in tests with a handheld scanner.

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Victoria Police initially called on Aldi to remove their $6 knife from sale in May.

But Aldi claimed they had withdrawn their request after being satisfied the blades were detectable.

And the state police force confirmed that to The New Daily on Friday, saying: “Victoria Police has accessed and tested the knives and although they are ceramic, they contain sufficient metal to active a metal detector.

“As such, they are not classified as a prohibited weapon.”

In a previous statement, Aldi claimed that a metal plate embedded in the handle of the product made them detectable by metal detectors.

Federal Infrastructure Minister Warren Truss said a ceramic knife “may” be detected by a combination of x-ray scanning, body scanners or metal detectors.

“Ceramic weapons and prohibited items can be routinely detected with a combination of these technologies,” a spokeswoman for Mr Truss said.

Sources inside Australia’s security forces said metal detectors can react to items like metal in ceramic knife handles in different ways depending on the sensitivity of the equipment.

This story has been updated to reflect a change in position by Victoria Police.