Controversial bookmaker Robbie Waterhouse has been censured after an inquiry into his published theory that bets can be placed with the TAB after a field has jumped.

In his newspaper column on March 30, Waterhouse cited an experiment conducted by licensed clerk Marc Lambourne who he said was able to place seven $1 bets at a tote window at Rosehill on March 28 after a race had begun. An eighth bet was rejected.

Racing NSW stewards said the records from the TAB and the Australian Prices Network disproved the experiment.

Stewards said they found "no evidence of any party or parties either being able to, or indeed, taking advantage of what occurred at the jump by placing or cancelling bets on the TAB".

They said updates of approximate dividends occur each 30 seconds of betting and the last update of the TAB market does occur when the race has been in progress some 30 seconds or approximately 500 metres.

While dividends do change after the start, it is part of the 30 second update.

Stewards also found speculation by Waterhouse concerning any delay in TAB close-off time attributable to the delayed Sky Channel picture was not relevant as the start, and therefore the close of betting, is not determined by the vision but by the broadcaster's audio.

Waterhouse was reminded that his position as a licensed person "requires comments he seeks to make and any conclusions he seeks to draw in his newspaper column, to be centred on a sound factual base rather than mere speculation, suspicion or on racecourse rumour".