"He is in a class of his own, it is hard to explain how good he is ... he is not human," Retief said.
English completed 26 laps of the course in a time of 23h 10m 20s. Second place went to Australia's David Rae who completed 25 laps (24:28:47) and third place went to Hamilton's Scott Ardern who also completed 25 laps (24:55:07).
Such was the size of his lead, English managed to finish almost an hour early to catch a flight back to Australia, and still won the event.
Liz Smith made it a double for Australia, winning the women's solo 24-hour title after completing 24 laps in 23:52:16.
"It was a pretty tough race. It took me a while to catch up to Anja [McDonald] but I'm stoked to have won," Smith said.
"It is the first time I have been here to Rotorua. With the world champs coming up next year I thought it would be a good chance to check out the trails and see what they are like."
She said she loved the trails and was looking forward to the 2016 World 24 Hour Solo Mountain Bike Championships being held in Rotorua next February.
The women's race was a lot closer than the men's, with Dunedin's Anja McDonald also completing 24 laps but in a slower time (24:23:36). Smith said she did not take the lead until the early hours on Sunday morning.
Rotorua's Leonie Smith rounded out the podium, finishing 21 laps (24:20:31).
The solo and teams 24-hour races started at 12pm on Saturday and finished at 12pm yesterday.
The winning 24-hour team was Team Chain Breakers who completed 29 laps.
The events on offer at the weekend included a 24-hour, 12-hour, six-hour, and three-hour race with about 190 people taking part.
Organisers said the weekend rain had no impact on the racing.
