A heavily criticised bill which would allow religious business owners in the US state of Arizona to discriminate against gay couples, has passed the final stage of the state’s legislature.

Senate Bill 1062 would prevent the state from taking action against individuals and businesses who refuse services to people or groups based on their religious beliefs if such enforcement would “substantially burden” the free exercise of their religion.

State Governor Jan Brewer has not said whether she will sign the bill into law.

On Thursday evening, the bill was approved by Arizona’s House with 33 votes to 27.

It has been described by Democrats as “state sanctioned discrimination”.

Idaho, Ohio and Kansas have all introduced such legislation, however the Arizona one is the most advanced.

It is unclear whether state Governor Jan Brewer will sign the bill into law.

Democrats have criticised Republicans over the policy.

“SB 1062 permits discrimination under the guise of religious freedom,” Senate Democratic Leader Anna Tovar said in a statement.

“With the express consent of Republicans in this Legislature, many Arizonans will find themselves members of a separate and unequal class under this law because of their sexual orientation.

“This bill may also open the door to discriminate based on race, familial status, religion, sex, national origin, age or disability.”

A similar bill was quashed by a Senate committee in Kansas yesterday – even though it had already won approval in the state’s House of Representatives.

Arizona has a statute that defines marriage as the union of a man and a woman. The state only legalised same-sex sexual activity in 2001.