Jackson said three of the group were between the ages of 16 and 20, while the other two were older.
The conditions over the weekend were "quite testing", Jackson said, with "big surf and quite a big drift from north to south".
"Because the tide was just changing, there was what we call a trough, which is the place in between the two sandbars and quite often that can drag people off the first sandbar and into that trough where it is quite deep."
He said the water was "well over" the swimmers' heads.
Although they did not need to go to the hospital or be seen by an ambulance, they were understandably "shaken up".
"If we didn't act when we did, it could have been a lot worse."
Jackson said it was a timely reminder for people to swim between the flags and put their hand up if they were in difficulty.
An hour before the incident occurred, at 1pm, a headcount found there were 1050 people both in the water and on the sand.
The incident was the second of the weekend, with one person having to be rescued from the beach on Saturday.
Despite these incidents, Jackson said conditions throughout the season had been "good".