US treasury secretary Jacob Lew said Sunday he was confident immigration reform would be adopted, despite strong opposition from some Republicans.
Last week the US Senate passed a controversial immigration bill that would give a path to citizenship for 11 million undocumented immigrants, and the legislation is now under debate in the Republican-controlled House of Representatives.
Conservatives have criticized the Senate version of the overhaul and have vowed any House version would need to have significant differences.
But Treasury Secretary Lew he thought the reforms -- strongly backed by President Barack Obama -- would become law.
"I think the immigration reform will pass," he said at a conference in Aspen, Colorado.
"We need to do this for the sake of the economy," he said, emphasizing that taxes paid by these newly legalized immigrants could help prolong the solvency of social security and medicare.
And he added, "we have to do it because it's the right thing to do. We have to it because it's the smart thing to do."
"We are a nation of immigrants. You look at the fortune 500 companies, 40 percent of them were started by immigrants or children of immigrants," he said.
The treasury secretary called himself "very optimistic" for US economic growth, saying there are "a lot of signs that there is a real recovery on the way."
But, he said, "we have to make sure we do not have another round of self-inflicted wounds," referring to negotiations over the country's borrowing limit and budget cuts, which hinder growth.
"I think the president has made clear... that we cannot be in a position ever again that you are negotiating over whether or not the US government is going to default," Lew said.
He refused to answer questions on monetary policy or to discuss the process to replace Ben Bernanke as head of the Federal Reserve, whose term ends in January.
Though media reports indicate the Treasury Department is involved in selecting his successor, Lew simply said his "conversations with the president should remain private."