Here are the General recommendations about in-water cleaning in Commonwealth waters:

• Commonwealth waters extend from the 3 nautical mile line (the limit of coastal waters) seaward to the 12 nautical mile line (the limit of the territorial sea).
• A slime layer on a vessel, regardless of origin, may be removed without full containment of biofouling waste, providing a gentle, non-abrasive technique is used.
• Macrofouling (fouling that has progressed beyond a slime layer) acquired from beyond the Australian Economic Exclusion Zone, should not be cleaned in-water if Condition D in the Decision Support Tool cannot be met (i.e. technology is not available to minimise release of viable biological material into the water column).
• Macrofouling acquired in another region within Australia should not be cleaned in-water unless a risk assessment determines that the biofouling is of low biosecurity risk. The coating should also be suitable for cleaning and the method used should not damage the coating surface or release amounts of contaminant into the environment that exceeds local standards or requirements.
• Locally acquired macrofouling may be cleaned in-water providing the coating is suitable for cleaning and the cleaning method does not damage the coating surface or release unsuitable amounts of contaminant into the environment. The biofouling waste does not need to be contained.
• Vessel owners/operators are encouraged to review the International Maritime Organization ‘2011 Guidelines for the Control and Management of Ships’ Biofouling to Minimize the Transfer of Invasive Aquatic Species’ (MEPC.207(62)) for further guidance on biofouling management practices.

Taken directly from : http://www.daff.gov.au/animal-plant-health/pests-diseases-weeds/marine-pests/anti-fouling-and-inwater-cleaning-guidelines/general-recommendations