An urgent warning has been issued to beachgoers about the unforgiving nature of ocean rips and the worst time to swim. 

The Bronte Surf Life Saving Club in shared a photo of the beach from above to show the dangerous and permanent rip current on the south end in full force.

While the 'tranquil' gap in the waves tends to look 'inviting', life savers warned it's the most dangerous spot to swim - even moreso after 7pm when the guards go home for the day. The warning was issued after the latest in a string of rescues at 8pm.

The club published a warning on social media, reminding swimmers that 'green water is not good water' and to consider swapping the sea for the ocean pool once the patrol period ends.

The rip can be seen as a passage of water or 'river of sea' between breaking waves. Currents are so strong even the best swimmers would struggle going up against it.

The Bronte Surf Life Saving Club in New South Wales shared a photo of the beach from above where a dangerous and permanent rip (left of the image) looks like the most appealing place to swim

The club published a warning on social media, reminding swimmers that 'green water is not good water' and to consider swapping the sea for the ocean pool once the patrol period ends 

'Commonly where the beach looks most inviting at Bronte is the most dangerous spot in at the moment!' the post read. 

'Where you see white water and waves usually to the north is where the red and yellow flags go up. It is where the waves tend to push you back to shore.' 

The reason why there are no flags at the south end of Bronte Beach is because there's permanent rip there. 

'The green water in the south end is where all the water escapes and heads back out to sea (along with people sadly) and this is the No Swim area at Bronte,' the post continued. 

'Let's make life a bit easier for the Lifeguards, Lifesavers and local surfers by only swimming between the red and yellow flags or if you are a weak swimmer go jump in the pool.

'The Lifeguards leave the beach at 7pm, and this is the time we ask to avoid the ocean but take advantage of the pool and stay safe this summer.'

The reason why there are no flags at the south end of Bronte Beach is because there's permanent rip there

According to , rip currents can be narrow or hundreds of meters long, and are of ten referred to by lifeguards as 'drowning machines'. 

The post was 'liked' by more than 2,500 people and hundreds left a comment.

'This information should be shared and shown on ALL incoming International flights to Australia,' one commented. 

Another wrote: 'Thank you for this great picture and green is mean reference. I swam at Bronte every summer in my youth and never heard that expression before. I'll take note of this now in my hometown beaches of Port Macquarie.'