The head of ASIO says there was no breach of national security arising from documents mentioning the intelligence agency that were found during a drug raid last month.

Victorian police found files from the Office of Police Integrity (OPI) along with documents from the Western Australian police and a job application for ASIO when they raided the home of a man suspected of drug offences.

ASIO's head, David Irvine, says the papers mentioning his organisation were job applications that were nearly 20 years old.

He told Liberal Senator Russell Trood he was concerned when he first heard ASIO documents had been found in the raid, but is now satisfied there was no breach.

"I'm advised by my people that no breach of national security occurred," he said.

"They were not classified documents. They gave away no national security information - that's welcome reassurance - I must say I agree."