"On day five, everything had gone magically, we had caught lots of fish, seen deer and had a great time and then this happened and suddenly I couldn't walk."
They were found by searchers on the Pukekahu track about 12.10pm on Tuesday and were flown out by the Lowe Corporation rescue helicopter.
The pair set out at the beginning of last week and were expected back about 5pm on Sunday, but the alarm was sounded when they failed to show for their shuttle.
"We come back every year for a week or two's holiday and try and go tramping somewhere or go fishing and try and catch up with relatives."
The pair had a tent and plenty of food to last for three days and knew they would be found "relatively quickly" because they had remained on the track.
Although he is an experienced tramper, the father had not heard of a personal locator beacon before the trip.
"Had I known about them I'd have taken one with me. I'd have pushed the button and the helicopter would have been there. It would have been a much better outcome for everybody."
"The professionalism from the police and Search and Rescue were great and the paramedics checked me out, winched me into the helicopter with my son, before checking me out thoroughly when we got to the other end."
The father and son spent the Tuesday evening in Ruatahuna before travelling back to Rotorua to be reunited with their family.
They had planned to do the crossing from Parahaki crossing over to Waikaremoana.
His son, who was unharmed in the ordeal, said it was "a bit scary" but he had tried to keep his mind occupied with little tasks.
He was keen to go for another trip, but was unsure if his mum would let him, confessing, "If mum lets us, I think I will.
"My dad wanted to do it since he was young so we thought we would do it together."
The father said "he was in there 40 years ago down to the Central Hut which was as far as we got last year, so I always wanted to go further.
"We didn't quite get there but maybe I'll be allowed to do it next year."