A lawsuit was filed by four couples in the US state of Arizona on Monday, which aims to remove the state’s ban on same-sex marriage.

The lawsuit was filed in federal court, and states that both a 2008 voter-approved state constitutional amendment banning same-sex marriage, and long-standing state law, both violate individual rights to equal protection and due process provisions of the US Constitution.

Judge John Sedwick has been asked by the suit to block enforcement of both provisions.

According to attorney Shawn Aiken, the bans are “arbitrary and invidious discrimination”.

“A state law that singles out homosexuals for disfavored treatment and imposes inequality on them” constitutes unequal protection, he argued.

He went on to say that Arizona’s laws block same-sex couples from receiving the “benefits and protections of marriage.”

At the very least, Aiken hopes to have the marriages of two of the couples, recognised in the state. He argued that the US Constitution currently requires the state to recognise opposite-sex out-of-state marriages, and that it has no legal right to decide that same-sex couples are not entitled to the same protection.

Two out of the four couples married in the state of California, which currently allows same-sex couples to marry.

The US Supreme Court last year struck down the Defense of Marriage Act (DOMA), which preciously forbid the government from recognising same-sex marriages in states where they are legal.

The organisers of a campaign to put equal marriage on a ballot in the US state of Arizona in 2014, back in September dropped the effort in favour of waiting until the next chance.