The detail of the legislation appeared to be forgotten in parliament as Assistant Treasurer Kelly O'Dwyer inadvertently supported a Labor amendment to a Government bill.
Ms O'Dwyer had been trying to pass the International Tax Agreement Bill.
But, instead, she accidentally endorsed an amendment put forward by Opposition assistant Treasury spokesman Andrew Leigh.
O'Dwyer: "I commend the bill to the House."
Speaker: "The immediate question is that the amendment be agreed to. All those in favour say aye. Okay. All those against? I think the ayes have it."
Andrew Leigh responded, sounding very pleased.
"Thank you, Deputy Speaker. At the outset, I'd like to very much thank the Minister as she leaves the chamber for voting for my second reading amendment. It's rare that one moves a second reading amendment in this place that is supported by the Government, but to have the House carry the second reading amendment was, indeed, a pleasing day for the Opposition."
The matter was quickly rectified, but it is an embarrassment for Prime Minister Malcolm Turnbull and his Government after winning July's elections with only a slim majority.
Manager of Opposition Business Tony Burke has told Sky News there has never been a more chaotic government.
"The bigger concern is you've got ministers with no idea what's happening when the laws of Australia are being passed, not paying attention, no idea what's going on. And it's a level of incompetence, it's not some ordinary administrative error. If it was an ordinary administrative error, this would have happened sometime in the last century. But it hasn't."
Last month, the Government lost three procedural votes in the House of Representatives when Labor caught out several ministers leaving parliament early.
Kelly O'Dwyer has responded to her error, calling the incident a stunt.
"Well, look, Labor has continued to play in this parliament a lot of adolescent games. And there was a procedural mistake last night, but it had no impact on the passing of the bill. And it's very, very clear that Labor wants to focus on game playing rather than focusing on their record and on a positive message."
But Opposition Leader Bill Shorten accuses the Government of not running parliament professionally, saying the blame goes to Christopher Pyne as leader of government business.
"They either don't turn up for parliament or, when they're in parliament, they vote for the wrong things. They've run out of work to do in the Senate. They can't add up basic numbers. What happened last night is the first time in the history of Federation. Since Australia became an independent nation, we've never seen a resolution condemning the Government supported by the Government. The only thing interesting about coming to parliament now is what's going to be their latest stuff up."
The Prime Minister's assistant minister, James McGrath, compares the Opposition to clowns.
He says the current clown craze sweeping the country has nothing on what he calls the "jokers" in the Labor Party.
"There's a craze here in Australia at the moment for people to go and dress up as clowns and go and find crazy clowns. Well, come down to Canberra, Ladies and Gentlemen, you don't have to go too far. You just have to look into the Labor caucus, and it is full of clowns. They may not have the crazy hair, they may not have the big nose that goes honk, or the lots of make-up, but Labor are the clown party."
