"They were struggling so I went out to get them with my kayak. It took me a good 20 minutes to get them back in and they were really tired."
Marshall said the pair had been swept away from the shore but were drifting left which made him worry for both his and the girls' safety if the rescue mission were to come across any big waves.
"It was just instinct. I would do it for anybody. There have been lots of kids at the campground lately because new families have joined so there are kids everywhere."
Marshall, who has been going to Blackhead Beach for 12 years, said the sea had been rough with strong and sometimes "very deceiving" rips throughout the long weekend.
"The thing is not to panic and just go with it. You may get taken right out but you'll eventually come out of the rip," he said.
The camp custodian, who did not want to be named, said Mr Marshall was a "reluctant hero" in what was a time of panic for those anxiously watching from the shore.
"The rip was going out and the waves were coming in so it was a fair time before he managed to get to them [the girls]. I think he really did save their lives."
Marshall said the beach rescue was a sure sign that those swimming at the Central Hawke's Bay beach weren't taking safety messages on board.
Summer swimming protocol was just as relevant now as in the warmer months, despite the clocks being turned back and the cooler weather approaching, he said.
As a committee member for the beach campground he said he would be advocating for more signage at the rural beach to better communicate the dangers of the water.
Two people died in separate drownings in the Hawke's Bay region over the summer.
On January 9, Amy Jenny Brown of Taupo drowned while trying to rescue a child at the Tukituki River mouth.
The next week, on January 14, Hemin Limbachiya drowned at Waimarama Beach after he and his wife, Tanvi Bhavsar, were caught in a flash rip and swept out to sea after Waimarama Beach Day.
