Queensland's sole One Nation MP invited 14 guests onto the floor of state parliament where they rifled through the desks of other politicians.
Stephen Andrew and his visitors' jaunt in the state's single chamber on Saturday night followed One Nation's annual general meeting and a glass of wine, and ended with a security guard moving the group on.
On Wednesday he told the House he was unreservedly sorry after his guests went through the desk compartments of other MPs.
It is unclear how many of them had been at the party's AGM.
Mr Andrew said the lids of desks were flipped open, but that it was dark inside the chamber and no one looked at the paperwork or personal belongings inside.
"It was a great evening, just to show people around," he later told journalists.
Mr Andrew said he had told his guests about parliamentary process and the building's history during their jaunt.
"I was just explaining about the gold from Gympie," he said.
"I was down the road beforehand ... we had a couple bottles of wine, there was actually half a bottle of wine still left over."
He said he didn't condone the behaviour of his guests and that he wasn't taking notice of where he was in the chamber when it happened.
"It was probably a sad thing that got away on me, I had my back turned and things get away," he added.
He has been barred by Speaker Curtis Pitt from bringing guests into parliament for six months.
Politicians began debating proposed anti-protest laws that activists and unionists say go too far, but which have been supported by MPs across the political spectrum.
The state government is clamping down on devices it claims could cause harm to the people using them and the emergency services personnel removing them.
The devices include complex contraptions known as the Dragon's Den or the Sleeping Dragon, but exclude household items like rope, glue, bike locks, chains and padlocks.
The government has taken issue with these devices because they are being used in mass environmental demonstrations that have repeatedly shut down the Brisbane CBD.
Other items known as mono-poles and tripods, used by protesters to stop coal trains, are also captured in the Bill.
Australian Associated Press