A NZ jockey has allegedly attempted to blackmail a local insurance broker over a $NZ100,000 ($87,000) bonus.

Darryl Bradley has been charged by the country's top racing body with attempting to extract some "money or other benefit" from Dunedin-based broker Fraser Macandrew Ryan (FMR).

The broker had reportedly arranged the underwriting for the bonus, which was to be paid if the same horse won all three legs of a treble.

Fritzy Boy had won the first two races ahead of Eel Win, which Mr Bradley was due to ride in the third race. The jockey has been accused of calling FMR to seek a payout in the event his horse won the race.

Ironically, the bonus became null and void as only eight horses - less than the stipulated minimum of 10 - ended up running in the race.

For the record, Fritzy Boy won again, while Eel Win was fourth.