Mr Jonker remained up above the cliff while his partner went down to the beach and watched from below.
The firefighters set up the lines to lower Mr Hayden down.
"Once the guy got down there and got friendly with the dog and chucked him in his arms, we hauled him back up," Mr Gardiner said.
Mr Jonker and another man helped firefighters pull Mr Hayden and the two-year-old wire-haired Jack Russell back up.
"We are very lucky to have him back," said Mr Jonker, who was grateful to the fire service for rescuing Reap.
He said the dog was chasing a ball when he went over the cliff.
"We were having a picnic, I took my eye off him and he went over.
"It was a massive relief when the fire service responded. At first I thought he was at the bottom of the cliff but he was on a ledge.
"If he had fallen two metres either side there was no ledge - the cliff is about 40 metres so we were pretty lucky."
Mr Jonker said Reap had first tried to find a way back up.
"Then he sat down and waited. The fireman walked across to him and he was basically, 'I'm in a bit of trouble here - are you here to rescue me? Sweet as'. He knew he was up shit creek without a paddle."
Reap suffered no injuries though "he's a bit quiet today" Mr Jonker said.
"I got my dog back - he's part of the family. They didn't turn their back on him."
The rescue took between 30 minutes and an hour, and it was lucky Wanganui firefighters could employ the pulley system, as their ability to use it was recently under threat. There are only a limited number of brigades allowed to use the lines to lower people down and pull them back up with pulleys, Mr Gardiner said.