Unions have warned they have a “nuclear-free defence policy”, sharpening differences between the Albanese government and the wider labour movement over the planned acquisition of nuclear-powered submarines.

ACTU president Michele O’Neil told the National Press Club on Tuesday that unions were seeking information from the government over the AUKUS plan, in which Australia will acquire second-hand US submarines in the early 2030s before locally built boats begin being delivered to the navy from the early 2040s.