A former union official and one-time boyfriend of Julia Gillard has thrown a punch at a photographer outside the royal commission into union corruption.

Bruce Wilson was spotted on Monday afternoon in a cafe near the royal commission building in Sydney, where his former union colleague Ralph Blewitt is giving evidence about alleged secret payments to a union slush fund.

Mr Wilson struck out at News Corp Australia’s Sam Mooy and shouted abuse as the photographer snapped him on the street.

The incident was captured by an AAP photographer.

Mr Wilson is yet to appear before the commission, which opened on Monday.

Mr Blewitt gave evidence on Monday that he went to Ms Gillard’s home in 1994.

He told the commission he was carrying $10,000 or $20,000 in cash when he went to the Melbourne home to meet Mr Wilson, his union boss and Ms Gillard’s boyfriend at the time.

Mr Blewitt told the commission Ms Gillard – who at the time was a lawyer with the firm Slater & Gordon – was at the front of the house when he arrived.

He said he met Mr Wilson in the kitchen or verandah where there were three other people doing renovation work.

Mr Blewitt said Mr Wilson called one of the workers over and asked Mr Blewitt to pay the man $7,000 from the cash he was carrying.

“I counted off $7,000, gave it to that gentleman. He stuck it in the front pocket of his bib and brace overall and went back outside to join the other two workers,” he said.

Mr Blewitt said Ms Gillard was not present when the money was handed over.

The former prime minister as previously has strenuously denied any wrongdoing and is adamant that she alone paid for her house renovations.