Police were observing a small group of demonstrators carrying placards opposing halal certification and sharia law when they were confronted by the anti-racism protestors.
One of the anti-Islam demonstrators, Nick Folkes, said he represented the Party For Freedom.
"We're opposed completely to ritual slaughter. Our set of values are completely different to Islam," he said
The Halal expo organisers says one of their aims has been to counter ignorance - as they push a message of food appreciation, tolerance and harmony.
"If they are really serious about any issue in this country, they have to take that issue with a friendly manner, with an harmonious manner," said director Syed Atiqul Hassan.
One major halal certifying agency told SBS it was not taking part in the expo because it doubts that all participants are in fact certified.
But organisers say they're confident that all stallholders are accredited.
