A device with radioactive substances that could pose a serious health risk if mishandled has been stolen from a vehicle in Ipswich.

Police are warning members of the public to be cautious after the portable density moisture gauge was taken from a utility on Byrne Street at Bundamba on Tuesday.

The gauge was locked in a transport case.

Detectives were investigating the incident and urged anyone who found the item to avoid touching it and instead call Triple Zero immediately.