Mark Latham has hit back with a furious spray after it emerged he was under investigation for allegedly abusing a racing official.

The Australian Turf Club (ATC) has launched an investigation into the firebrand politician after he allegedly abused the organisation's head of corporate affairs and government relations, Steve McMahon, in the Members' grandstand at Rosehill Gardens on Tuesday.

The ATC told the Daily Telegraph the 'incident was witnessed by several people” and involved 'alleged unprovoked verbal abuse'.

It’s understood multiple f-words were exchanged during the verbal altercation.

But when approached by Daily Mail Australia, Latham defended his actions in an extraordinary spray. 

'Someone had to tell McMahon what everyone thinks of him,' the former Labor leader said. 

'With Peter Putin (believed to be a reference to Peter McGauran, chair of the ATC) calling off the vote because it was losing, how else can the members get their opinion across?'

'The D***wad came over to me again, making out he’s my friend. Last time he does that.'

The altercation was sparked by the long-running Rosehill Racecourse saga, with members promised a vote on fast-tracked, $5billion plan to turn it into a 'mini-city' of 25,000 homes.

But regulator Racing NSW announced on Friday it had instructed the ATC to postpone the vote until May 12, over concerns about 'insufficient' information being provided to members. 

The unsolicited project, which hasn't had full architectural drawings made, was reportedly fast-tracked after an informal meeting between NSW Premier Chris Minns and the the ATC's Mr McMahon. 

But in December it emerged that Premier Minns will be referred to the Independent Commission Against Corruption over accusations he failed to declare a 20-year friendship with Mr McMahon. 

Latham added: 'He started this whole s***show yet he swans around the racetrack like Forrest Gump. 

'Someone had set him straight.'

Daily Mail Australia has approached the ATC for further comment.