The date has been set for the first same-sex couples to use British laws to marry in Australian cities.

Same-sex couples in which one partner has British citizenship will be able to marry from June 27 in British consulates in Sydney and Perth, with Melbourne, Brisbane and Canberra to follow soon after.

Same-sex marriage campaigner Rodney Croome has welcomed the date for couples to get married in Australia under British law. Credit:Graham Tidy

In a move that will increase pressure on the Abbott government to allow a conscience vote on marriage reform, hundreds of Australian couples are expected to marry and can begin the process to book ceremonies in Sydney or Perth from Thursday.

The Abbott government signalled in March that it had no objection to British consulates in Australia being used to host same-sex weddings after same-sex marriage was legalised in England and Wales.