A proposed ban on same-sex marriage in Florida lacks the voter support needed to pass, a poll indicates.

The South Florida Sun-Sentinel reported Sunday that the ballot measure -- Amendment 2 -- would amend the state constitution to bar gay marriage.

A Sun Sentinel and Florida Times-Union poll reveals 53 percent of 600 likely voters said they supported the plan, far short of the 60 percent approval required for the constitutional amendment.

The poll found 77 percent of likely voters favored equal rights for same-sex couples, while 15 percent were opposed and 8 percent were undecided.

Although gay marriage has been prohibited in Florida for more than a decade, supporters of the proposal say enshrining the ban in the state constitution would protect the measure from court challenges.

The amendment would specifically define marriage as between a man and a woman, and would say that no "substantial equivalent" is legal either.

Opponents say if the measure passes there could be court challenges to domestic partnership benefits, including hospital visitation rights.