A man has been arrested after police seized a loaded firearm and drugs believed to be steroids from the Bandidos bikie clubhouse in Melbourne's north.

The police raided properties in Brunswick and Doveton in Melbourne's south-east on Thursday as part of the anti-bikie Echo Taskforce.

The Bandidos clubhouse in Brunswick is pictured in 2016. Credit:Pat Scala

The State Emergency Service assisted police with floodlights, as it was still dark, at an address on Weston Street in Brunswick on Thursday morning, a spokeswoman confirmed.

Along with the firearm and drugs, a 48-year-old man was subsequently arrested at the Brunswick property, and charged with possessing an unregistered handgun and unlicensed ammunition as well as a drug of dependence.