'While the worst of the heavy rain and strong winds appears to have passed, the conditions on lakes and rivers from Hunter to Tweed Heads is still not ideal for boating,' RMS Principal Manager Northern Sonia McKay said.
'The Macleay and Hastings Rivers are the two worst affected rivers and have copped the brunt of the flood conditions.
'There are many submerged and semi-submerged hazards such as trees and other floating debris in the water.
'Many navigation aids such as buoys and channel markers have been moved and are not in the correct location.
'Boating Safety Officers are working hard to mark hazards and reinstate navigation aids but it could be some time until the process is completed.
'Boaters are asked to be patient and if they need to head out on the water, to ensure they do so slowly and cautiously.
'Anyone who finds a navigation aid should call 13 12 56 to report it.
'Trailer boaters should also be aware there is a lot of siltation on boat ramps where flood waters have risen much higher than normal over the past couple of days making them very slippery.
'In Port Macquarie an 80 foot pontoon with a jetski attached to it broke away and was last seen floating down the Hastings River.
'Several vessels also broke away from moorings in Lake Macquarie.
'The good news is people have heeded weather warnings and there have not been any reported incidents over the last couple of days, which is commendable.
'Anyone going boating should use extra caution until conditions subside, waters recede and all known hazards are again marked,' Ms McKay said.