Labor’s longest serving foreign minister says the submarine plan is likely to be regarded as one of Australia’s worst foreign policy and defence errors.

A former ambassador to the US has dismissed criticism of a change in the AUKUS pact, as critics launch a fresh push to walk away from the deal.

A frustrated Penny Wong and Richard Marles have told AUKUS critics the controversial submarine pact is meeting milestones, despite setbacks with its UK partner.