Warrnambool SES unit controller Giorgio Palmeri said there had been five near drownings at the blue hole in the past 18 months.

"There have been several near drownings, mainly involving people who underestimate the power of the ocean who went for a swim or people have gone in after a dog," Mr Palmeri said.

He said one young woman, who went in after her dog, was particularly lucky to escape with her life.

"Sometimes the mouth of the river can be very calm and safe but at other times - especially this time of year - the mouth is open and there is lots of flow from the Hopkins," Mr Palmeri said.

He said that in addition to very strong currents, the sand was very soft.

"You need to stay very clear from the edge," Mr Palmeri said.

"The sand is fairly steep and soft and the ground can give from under feet and once you're in the water it can be almost impossible to get back to shore."

Mr Palmeri urged people to remain vigilant at this popular walking spot.

"People underestimate how dangerous it can be," he said.

Warrnabool Surf Life Saving Club (WSLSC) captain Jo McDowall echoed Mr Palmeri's sentiments.

"WSLSC always encourage beach goers to swim between the flags whenever possible and preferably at a beach that usually has a lifesaving service in operation," Ms McDowall said.

"Exploration around water, particularly rocky outcrops that can be over-run by waves or paddling at the edge of strong flowing rivers or at unpatrolled beaches carries increased risk.

"Fifty per cent of Victorian drowning incidents in 2019/20 were due to unintentional water entry from slips, trips, falls or attempting a rescue.

"We ask families to stop, look and plan before they carry out activities around water."

Mr Palmeri also took the opportunity to warn people not to attempt to drive through flood waters.

Earlier this month, the SES was called to rescue a Terang man who had become trapped in flood water at Cobrico.

"It was around 11pm at night and when we arrived the man was sitting on the roof of his car," Mr Palmeri said.

"He was very lucky he had a mobile phone so he could call for help."

Mr Palmeri said he also wanted to remind people to obey signs when enjoying one of the ocean walks in the city.

He has witnessed people edge dangerously close to the edge of cliffs at locations including Thunder Point in search of the perfect selfie.

"People wander around off the track and they don't realise the ground can give in," Mr Palmeri said.

"They can fall or lose their balance and hurt themselves."

The near drownings included a 20-year-old woman who went to the aid of her dog in September last year.