A farmer has been killed in a quad bike crash on his sheep, beef and stud farm near Wairoa, in the northern Hawkes Bay.

Kevin David Knauf died when his quad bike rolled 40m down a steep bank on his 2000ha station Tangiwai on Monday afternoon.

It is understood the 59-year-old had been working stock by himself when the accident happened. It was only when he failed to return home that night that a relative went to look for him and discovered the crash.

The Lowe Corporation Rescue Helicopter arrived too late to help him.

Jon Knauf last night described his father as a much loved husband, father and father-in-law of four and grandfather of seven.

Alastair Milne told the Herald he met Mr Knauf through business and they became close friends.

"He was a self-made man, if you like, who worked his way up from nothing. He always had a dream to own his own station and he did the hard yards."

Mr Milne said Mr Knauf started out as a share milker and realised his dream of owning a station through "good honest toil".

Mr Knauf won King Country farmer of the year in 1985 and was a well-respected farmer who set goals for himself and achieved them.

"It seems strange that Kevin is gone. He was a bit like a totara tree - he was a strong character, both physically and mentally," said Mr Milne.

The police and the Department of Labour are investigating the cause of the crash and the death has been referred to the coroner.

More than 100 people have died on quad bikes in the past decade and coroners have previously called for law changes concerning the bikes.

Wellington coroner Ian Smith criticised Parliament last July for failing to make changes.

At an inquest into a quad bike death near Masterton in 2008, Mr Smith said coroners had repeatedly asked for law changes to make it mandatory for quad bikes to be fitted with roll bars and seatbelts, and to force riders to wear helmets. He said it was time Parliament put the recommendations in place.