Customs Act 1901

If after any agreement is made for the sale or delivery of goods duty paid any alteration takes place in the duty collected affecting such goods before they are entered for home consumption, or for export, as the case may be, then in the absence of express written provision to the contrary the agreement shall be altered as follows:

In the event of the alteration being a new or increased duty the seller after payment of the new or increased duty may add the difference caused by the alteration to the agreed price.

In the event of the alteration being the abolition or reduction of duty the purchaser may deduct the difference caused by the alteration from the agreed price.

Any refund or payment of increased duty resulting from the alteration not being finally adopted shall be allowed between the parties as the case may require.

Subsection (1) does not apply in relation to duty imposed by the Customs Tariff (Coal Export Duty) Act 1975.

Subsection (1) does not apply in relation to duty imposed by the Customs Tariff (Uranium Concentrate Export Duty) Act 1980.