For appropriation bills in the House of Representatives, a message to the House from the Governor-General recommending the purpose of the appropriation in accordance with section 56 of the Constitution must be announced before the bill is introduced. A further message must be received before any amendment can be moved which would increase, or extend the objects and purposes or alter the destination of, a recommended appropriation. This requirement in effect prevents private Members from moving such amendments. However, a private Member may move to reduce the amount of a proposed expenditure or may move to omit items.
Section 53 of the Australian Constitution states that:
The Senate may not amend proposed laws imposing taxation, or proposed laws appropriating revenue or moneys for the ordinary annual services of the Government.
The Senate may not amend any proposed law so as to increase any proposed charge or burden on the people.
The Senate may at any stage return to the House of Representatives any proposed law which the Senate may not amend, requesting, by message, the omission or amendment of any items or provisions therein. And the House of Representatives may, if it thinks fit, make any of such omissions or amendments, with or without modifications.