Yesterday, National Distribution Union secretary Robert Reid told RadioLive he sat behind Mr Williamson and had not heard him swear.
"But he certainly was getting very excited ... He was punctuating his comments by pointing his finger at Aussie players and at the ref when decisions went the wrong way."
Mr Reid said Mr Williamson had also booed at points, but so had he. He was not a fan of the minister, but his behaviour was part of the general atmosphere in the box.
He said the Australians nearby "were not very happy-looking people ... but I think that was probably [due to] the scoreline at that point as well".
A spokesman for Len Brown said the mayor knew who the minister in question was but would not name him and had laughed about his actions.
A spokesman for Australian High Commissioner Paul O'Sullivan, who was in the VIP box, said he had not noticed anything so had little to say.
Mr Williamson was one of three ministers in the VIP area. Other guests included Australian Rugby Union officials, Mayor Brown, ex-Wallaby Phil Jones and Italy's ambassador.
The other two ministers were Wayne Mapp and Jonathan Coleman, who both said they did not notice any bad behaviour.