The largest slipway in northern Australia is 3000 tons and 105 metres at Tropical Reef, Brisbane.
Sydney has a 65m floating dock capable of accommodating up to 1000 tons and a 365m graving dock capable of accommodating 110,000 tons.
Then you have the 156m 9,300 ton shiplift at Osborne (capable of being upgraded to 20,000 tons)
There was also the State Dockyard at Newcastle/Carrington which had a 15,000 ton floating dock until the 70's and a number of slips ultimately closing for good in 1987. The rest of the maintenance capacity in Australia is 100 & 200m wet docks.