The discovery of hazardous materials in an able seaman’s bedroom sent a Victorian naval base into lockdown, but it turned out to be nothing suspicious.

The 30-year-old able seaman has been released from police custody without charge after the bomb squad cleared the materials found at the HMAS Cerberus base.

The base was locked down as a precaution on Thursday after a combination of “unusual hazardous materials” was found in a residential unit during a routine search.

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The 30-year-old was being released from custody without charge, police said.

“Victoria Police have found nothing suspicious and there will be an internal investigation, if they need to, by the Navy,” a Victoria Police spokeswoman said.

Police and Defence have not released details of what the materials were, other than to say they did not appear to be explosive.

Superintendent Neil Paterson said it was the combination of the materials, which would not normally be found in a residential unit, that had caused concern.

“It’s not a large quantity of materials but the materials that we have found are hazardous and not normally found in barracks on this location,” he told reporters at the Mornington Peninsula base.

A 400-metre safety zone was put in place around the unit as a precaution while the bomb squad carried out a thorough investigation of the materials.

Supt Paterson said there was no risk to any of the up to 2600 people who work on the naval base.

“The personnel, staff that are on the base here are very safe indeed,” he said.

“There has been no immediate threat given the nature of the materials and no life has been at threat here on the site.”

Supt Paterson rejected links to terrorism.

“This has no relevance or bearing to anything that is happening anywhere else in the world at this point in time,” he said.