Labor said the mistake is unprecedented in the federal Parliament, the first time a second reading amendment has passed the House of Representatives and leaving uncertainty about how the government could unwind its position.
Manager of Opposition Business Tony Burke blamed Financial Services Minister Kelly O’Dwyer, who he claimed had forgotten to vote against the amendment on behalf of the government, meaning it passed unanimously.
The amendment, moved by shadow assistant treasurer Andrew Leigh, called on the government “to explain why it has failed to close tax loopholes and increase transparency in Australia”.
Mr Burke said the mistake made the Coalition the first federal government in Australian history to vote against itself.
He accused the government of overseeing chaos in Parliament and said he expected more errors in the future.
“For the first time since Federation in 1901, tonight the government has voted in favour of a second reading amendment,” he said in a statement.
“The Liberals have called on themselves to explain their failures.”
Speaker Tony Smith intervened after 7pm, with Labor cooperating to remove the amendment and allow the original bill to pass.
The strategic win by Labor comes a month after the government lost three procedural votes on the floor of the House of Representatives when senior ministers left the chamber early and allowed Labor to defeat an adjournment motion.
Immigration Minister Peter Dutton, Justice Minister Michael Keenan and Social Services Minister Christian Porter were absent from the chamber at the end of the first sitting week, allowing Labor to come close to passing a motion calling for a royal commission into the banking sector.
Leader of the House Christopher Pyne blamed the mistake on “an inadvertent error”.
“I would make the point that there are several owners of this error and I am not going to criticise them individually, because it is wrong to criticise the people who work for us, the people who were sitting in the chair . . .” he said.
“There was a series of events that led to this outcome and it is a pity.” The situation has the potential to create new precedent for the House of Representatives.