The US state of Louisiana’s Department of Revenue has announced it won’t recognise same-sex marriages on state tax returns, despite a new IRS rule that allows legally married gay couples to file joint federal tax returns.

Revenue Secretary Tim Barfield said that Louisiana can’t recognise a same-sex marriage tax filing because of the state’s constitutional ban, according to a document outlining the state’s position.

Barfield said that Louisiana’s constitution trumps a Louisiana law requiring taxpayers to use the same filing status on state and federal tax forms

In his guidance to taxpayers, Barfield wrote: “Louisiana’s secretary of revenue is bound to support and uphold the Constitution and laws of the state of Louisiana, and any recognition of a same-sex filing status in Louisiana as promulgated in (the new Internal Revenue Service rule) would be a clear violation of Louisiana’s Constitution.”

Approved by lawmakers and voters in 2004, the Louisiana state constitution defines marriage as between a man and a woman and declares that a legal status of marriage for any other couples “shall not be valid or recognised.”

Barfield said that a gay couple filing as married on a federal tax return must file a separate Louisiana return as single or head of household.

The rules mean that married same-sex couples will be deprived of any tax benefits that are granted specifically to married couples in the state.

Barfield added: “The taxpayer must provide the same federal income tax information on the Louisiana State Return that would have been provided prior to the issuance” of the IRS ruling.

The news follows a similar announcement in the US state of Wisconsin. Last week, it was reported that some same-sex couples in the state might file their tax returns jointly in defiance of the decision.

The US Treasury Department and the IRS issued their new rules two weeks ago, saying all legally married gay couples will be able to file joint federal tax returns even if they reside in states that do not recognize same-sex marriages.