It happened about midday on Saturday as Vaughan Wenham and his stepson were coming up to a slope.
Wenham was taken to North Shore Hospital and is now recovering at home with a swollen throat and whiplash.
His brother Darren Wenham said the wire hit Vaughan at the top of his shoulders and his throat.
"It completely whipped him off his bike. The injury to him could have been fatal if he was going any faster. He was only doing 20km/h at the time. "
Darren Wenham said the iwi who owned and managed the park had been very helpful.
But police said it appeared the man rode off the track and into the wire.
A police spokesman said police investigated the incident and determined the wire was farm wire, consistent with wire being used for stock maintenance.
He said the incident appeared to be an accident and there was no further police action being taken.
