The Rivers Casino is delaying its opening by four days because of water damage to slot machines during last week's storms.

In a statement this morning, casino officials said they had asked the state Gaming Control Board to push back the opening from Aug. 5 to Aug. 9. They said the request was a result of minor water damage to a small number of slot machines during the bad weather as well as damage to some slot machines during their transport to the North Shore venue.

George Matta, a casino spokesman, said about 50 machines were damaged during last week's rains. He did not know how many others were damaged during their transportation to the casino.

"While we continue to experience great progress in the final weeks of construction, the additional four days gives us adequate time to resolve both issues and provides a few extra days to ensure that the grand opening is flawless," said Ed Fasulo, the casino president and chief operating officer, in a statement.

Gaming board Executive Director Kevin S. O'Toole approved the request this morning, spokesman Richard McGarvey said.

"It's not the first time. Others have asked to move the [opening] day back. Usually with something like this, you can't predict everything that's going to happen," he said.

The Rivers Casino also will move back test days originally scheduled for Aug. 1 and Aug. 3 to Aug. 5 and Aug. 7.