An effort to repeal a gay marriage law in Washington state was launched by opponents on Monday, just hours after Governor Chris Gregoire signed the bill into law.

Gay and lesbian couples will be allowed to marry in the state starting on June 7 provided opponents do not gather sufficient signatures to put it up for a vote. In that case, marriage equality would be put on hold pending the outcome of a November election.

The effort is backed by the National Organization for Marriage (NOM) and the Family Policy Institute of Washington.

“Preserving marriage as the union of one man and one woman is worth fighting for,” said NOM President Brian Brown. “Marriage is the cornerstone of society that not only unites a couple to each other, but ensures that any children born of their union will have the best opportunity to be raised by their own mother and father. We're committed to giving Washington voters the right to decide the definition of marriage in their state, just as voters in 31 other states have been able to do.”

In a statement posted at its website, the Family Policy Institute of Washington said: “We ARE going to exercise our right to referendum and reject this law.”

In her remarks before signing the legislation, Gregoire touched on the upcoming fight to keep the law in place.

“If asked those questions with their heads and their hearts, I believe the people of the state of Washington will say, 'Yes, marriage equality is right for our state and our time is now. The time is today,'” she said.

Voters in 2009 rejected an effort to repeal a domestic partnership law which gave gay couples all the protections of marriage.