The federal government's claim that it "stopped the boats" has been called into doubt by analysis showing asylum seeker arrivals slowed dramatically after the former Labor government toughened its border stance, suggesting the Coalition "vastly overrated" its contribution.

The analysis, by former Immigration Department chief John Menadue and Australian National University migration expert Peter Hughes, shows the drop-off began immediately after former Prime Minister Kevin Rudd announced in mid 2013 that asylum seekers who arrived on unauthorised boats would never be resettled in Australia.

When Prime Minister Tony Abbott took power a few months later "the flow of maritime arrivals was well on its way to being finished as a result of measures already taken" by Labor, the analysis said, adding the Coalition's role "was at the margins and vastly overrated".