By Kay Henderson

DES MOINES, Iowa (Reuters) - Iowa took a step toward legalizing on-line poker on Tuesday because supporters said the state is losing millions of dollars in revenue annually to companies outside the state and overseas running the games.

The Iowa Senate voted 29-20 in favor of legislation that would give state-licensed casinos authority to run poker games online for patrons as long as the computer and the person are located in Iowa.

Nevada and the District of Columbia have voted to legalize online poker but are still drawing up the rules to regulate it.

Democratic Senator Jeff Danielson said Iowa residents wager an estimated $30 million in online poker games every year, money that is often going to overseas companies running the online games.

"That's a problem for our overall economy to see that kind of leakage," Danielson said.

Iowa Republican Governor Terry Branstad said he is open to considering the bill.

"In terms of regulating and controlling gambling in this state, our top priority has been to keep it honest, clean, open, transparent and keep the criminal element out," Branstad said.

Branstad is in his fifth term as governor. During that tenure Branstad has signed bills legalizing parimutuel racing and creating a state-run lottery as well as a series of casino-related bills. There are 17 state-licensed casinos operating in Iowa, all of which could contract with an internet provider to run on-line poker games if the bill becomes law.

While 20 senators voted against legalizing on-line poker, none of the opponents voiced objections during senate debate of the bill. It is unclear whether the legislation can survive a deadline in the Iowa House, as the bill must clear a committee in the House by Friday to remain eligible for debate.

(Editing by Greg McCune)