LOS ANGELES (REUTERS) - Legislation to allow online poker gambling in the United States (US) will be introduced in Congress that would give casinos a larger market than the current few states which allow it, like New Jersey and Nevada.

Online poker would generate US$10 billion (S$13 billion) in added revenues by 2017 if allowed by federal statute, according to the American Gaming Association. About US$4 billion is now being spent for illegal sites, the AGA said.

US casinos have been slow to launch online poker sites because the slow pace of state approvals doesn't allow them to cross state lines to attract more gamblers and bigger winnings.

MGM Resorts International believes Nevada may be too small a market for it to serve with an online site, Chief Financial Officer Dan D'Arrigo told Reuters.

The bills will likely face opposition by state legislatures and lottery officials.

If passed, the legislation would allow the federal government to preempt states like Nevada and New Jersey that are moving ahead with their own laws and accelerate efforts in states like California and Illinois that are considering such legislation.

Congressmen Peter King, a Republican, and Joe Barton, a Democrat, will each introduce bills, according to aides.

Previous bills in Congress have failed. The bills, as currently contemplated, would allow individual states to opt out of federal online poker requirements.