Six men - all in their teens or early 20s and described as members of a "Middle Eastern crime syndicate", some from the same family - have been arrested over last week's armed robbery at a gun shop in Melbourne's north.

Police investigating the heist at Frank O'Reilly's Sports in Thornbury made several arrests in the past 24 hours, beginning with a broad-daylight arrest at a Docklands apartment involving the Special Operations Group on Monday.

Handguns were stolen in an armed robbery at this Thornbury gun store last week. Credit:Larissa Ham

Police had feared the stolen guns - 37 in total - would be sold on the black market but they now believe all the missing firearms were recovered in the Docklands apartment.

Police found the handguns during the Docklands raid, with two men - aged 18 and 20 - arrested after trying to evade police through the underground car park of the Collins Street building.