One of New Zealand's most successful Olympic sports, rowing, was in turmoil on Thursday with celebrated coach Dick Tonks threatening to defect to China eight months out from the Rio Games.

A feud between Tonks, who has coached multiple world and Olympic champions, and rowing bosses erupted after he refused demands to stop assisting a Chinese crew based in New Zealand.

Rowing New Zealand (RNZ) chief Simon Peterson said Tonks had to choose between New Zealand and China.

"He decided to go with the Chinese. He has walked... and wants nothing to do with us at RNZ," Peterson claimed on Radio Sport.

Tonks, 64, maintained that assisting overseas crews was not new and he was angry his dispute was being played out in the media.

"I've been undermined at different times with no consultation at all," he told TV3 of his relationship with rowing bosses.

"You don't normally conduct these things in the press and that's very annoying. And the statement that they are in consultation with me when they are not, is also highly annoying."

Tonks is currently the personal coach of two New Zealand Olympic medal prospects -- defending single sculls champion Mahe Drysdale and the world champion women's doubles team Zoe Stevenson and Eve Macfarlane.

While Drysdale and his management team attempted to heal the rift, Tonks said he was weighing up an offer to coach in China.

"Now I have another option on the table in front of me that secures my future," he said.

Tonks has coached 13 world champions and six Olympic gold medallists.

He has taken the New Zealand team to five Olympics including London in 2012 where they were the second most successful rowing nation with three gold and two bronze medals.
Source: AFP