Four US state National Guards have said they will not follow a Pentagon directive to enrol same-sex couples in benefit programs, all citing their state-wide bans on equal marriage.

The 3 September saw the benefits kick in. The Defense Department had announced that couples in same-sex marriages performed in states where it is legal would be recognised as legally married, following the Supreme Court’s ruling on the Defense of Marriage Act (DOMA), back in June.

Last week also saw the first day on which military service members could apply for special leave of up to ten days to allow same-sex couples to travel to a US state where equal marriage is legal, in order to marry.

The refusals of Oklahoma, Texas, Mississippi and Louisiana states are unlikely to block same-sex couples from receiving the benefits, which will still be available through enrolling at federal installations, however are being seen as a preview of a bigger battle over benefits still to come.

On Tuesday, Oklahoma Governo Mary Fallin notified the National Guard in her state that processing benefits would violate the state-wide ban on equal marriage.

Other states my also join the four, as Florida Attorney General Pam Bondi last week declined to offer an opinion on whether her state’s National Guard will process the benefits.

The fact that some National Guards are refusing will not necessarily mean gay troops can’t add their partners to benefit programs. They will only be unable to do at state-run facilities.

When National Guards are inactive, they are under the command of a state governor, not the Department of Defense. The Florida National Guard is advising gay troops that they can sign their partners up at federal facilities.

The decision by the National Guards was widely condemned by LGBT military groups, some accusing the organisations of “playing politics” with military families’ lives.

“The issue is really a matter of where enrolment can happen,” said Brian Moulton, legal director at the Human Rights Campaign. “We are not aware of Guard members with same-sex spouses being unable to secure benefits through a federal facility.”

Some have suggested court action over the refusal to follow the directive, although others have suggested that the burder of having to travel to a federal facility would be insufficient basis for a court challenge.

The National Guard in the US states of Texas and Mississippi last week refused to process benefits requests from same-sex couples, despite the Pentagon directive.