Rowing New Zealand has split with one of their most successful coaches.

Richard Tonks, who coaches the likes of Mahe Drysdale and has mentored Rob Waddell as well as Hamish Bond and Eric Murray in the past says he's finished with the organisation.

It's after his link with a Chinese crew was questioned.

Tonks had been working with a Chinese pair on Lake Karapiro, the same training base that New Zealand rowers train on.

Dick Tonks says he was working with a provincial Chinese pair that were working towards the Chinese Games in 2017 and hence wouldn't be opposition to any New Zealand rowers.

Tonks says it's nothing that hasn't been done before and plenty of crews have trained in New Zealand before.

Mahe Drysdale, who currently works with Tonks was shocked to learn of the falling out and didn’t want to lost his coach seven months out from the Rio Games.

Dick Tonks won the Halberg Awards Coach of the Year five times and has coached crews to at least 25 world championship medals and five Olympic golds.

It’s understood the relationship between Tonks and Rowing New Zealand has been strained for some time.