After the Republican Policy lunch, which included a briefing on his trip to Europe, the president said he understood immigration is a "highly emotional issue" for lawmakers. A compromise immigration bill collapsed on the Senate floor last week.
"But those of us standing here now believe now is the time to move a comprehensive bill that enforces our borders and has a good workplace enforcement, that doesn't grant automatic citizenship," Bush said in a statement.
White House spokesman Tony Snow said Bush had talked about illegal immigration when he visited Mexico earlier this year.
"They continue to be the subject of Cabinet-level conversations between the two governments," Snow said, adding regional development in Latin American had been the focus of talks.
The Washington Post said Bush changed few minds with his rare appearance at the closed-door GOP Senate lunch.
"We're off the bill," Sen. Jeff Sessions, R-Ala., told the Post. "We ought to stay off the bill for awhile."