Merimbula Marine Rescue has warned that skippers need to take extra care when crossing the Bar after a number of incidents which required Marine Rescue to assist.

Due to the continual movement of the sands and forming of new channels near the spit on the Mitchies Jetty side, there is often a cross current causing waves from more than one direction at times making crossing the Bar particularly hazardous when the tide is going out (ebbing tide).

Sonia Tester at Merimbula Marine Rescue said the movement of sand has meant the channel is not so distinctive. The changes have resulted in the Marine Rescue vessel only being able to cross the Bar three hours before high tide and two hours after high tide.

She advised skippers to have some local knowledge of the bar before crossing it, even spending some time observing it when the tide and sea conditions are the same as when it is intended to cross it.

"When you are coming in, sit behind a wave with the bow slightly raised and give yourself plenty of time to negotiate the S bend channel," Ms Tester advised.

She also warned that you have to commit to the crossing and not turn back in the middle of it as that could place the boat in danger of being swamped and turning over as the waves hit side on.

"If you are in any doubt, don't do it," Ms Tester said.

But despite the shifting sands at the Bar, there appears to be plenty of people wanting to get out in their boats.

"We've been very busy with lots of log ons all along the coast, which is good," Ms Tester said.

"We're a lot busier than we would normally be at this time of year. Usually at this time we might expect one or two boats a day but we're seeing 10-12 boats a day," Ms Tester said.

She believes the Bar will self-correct, saying that as the channel gets smaller the water will have more of a scouring effect and start to reverse the process.

"It was much worse prior to the East Coast Low (in 2016). It will return, it's just mother nature. What we really need is a decent storm to push it all out," Ms Tester said.

NSW Maritime has reminded skippers that conditions can change quickly saying that if the weather looks bad including unfavourable conditions such as heavy swells, strong wind, breaking waves, or the tide is running out, it is best not to try to cross a bar.

Waves with a longer period typically move at faster speeds and with more volume of water in the wave, resulting in more energy, and the wave will generally be larger with more force when it breaks. There can also be more of a lull between sets of larger waves, which can catch-out boaters crossing a bar.

Marine Rescue urges everyone going out over the bar to log on with Marine Rescue Merimbula either via VHF radio - Channel 16, or by the free MRNSW phone app.

NSW Maritime has produced a guide to safely crossing bars you can download. Read the guide to find out the best and safest way to approach a bar when going out, and when coming back in.

Always wear an appropriate lifejacket when crossing a bar in any boat at any time, and make sure it's worn correctly and securely.