A brawl has erupted at a southern Sydney cafe where a Liberal Party branch meeting was taking place on the eve of the state budget.
Officers "saw numerous people running from the location" when they arrived at the Arncliffe business about 7pm on Monday, NSW Police said.
A man in his 40s was taken to St George Hospital with minor injuries.
"Police are now attempting to piece together exactly what happened and how many people were involved," NSW Police said in a statement.
They urged anyone with footage of the incident to contact authorities.
A Liberal Party spokesman said the party was aware of the incident and was cooperating with police.
"An internal investigation will also be undertaken and disciplinary action taken against those responsible," he said in a statement to AAP.
"The Liberal Party strongly condemns the kind of behaviour that is alleged to have occurred."
The brawl comes ahead of Tuesday's state budget, with Treasurer Dominic Perrottet planning to mix record infrastructure spend with tax cuts and concessions.