The Australian High Court on Friday announced that it would hear an expedited challenge to the nation's first gay marriage law.

Last week, the Australian Capital Territory (ACT) approved a law allowing gay and lesbian couples to marry in the territory, which includes Canberra, the nation's capital. The law is expected to take effect in early December.

Prime Minister Tony Abbott, whose conservative Liberal-National coalition swept into power on September 7 on a pledge to lower taxes, filed a legal challenge to the law, arguing that only the federal government has the power to regulate marriage.

After a short hearing on Friday, Chief Justice Robert French signaled that the case could be heard in early December.

Abbott, who has repeatedly stated his opposition to marriage equality, warned gay couples from marrying in the ACT until after the High Court has ruled on the legislation's validity.

“If as I think the ACT legislation turns out to be invalid under the constitution, well then those marriages wouldn't be valid,” Abbott told 3AW. “So I'd suggest to people who would like to be married under the ACT legislation – hold on 'til its validity is tested.”

(Related: Gay sister's engagement fails to move Australia's Tony Abbott on marriage equality.)