US President Barack Obama has said that he expected the Senate would start debating comprehensive immigration reform next month, putting an optimistic spin on the legislation's prospects.

In an interview with the Univision Spanish-language television station, Obama praised a bipartisan group of Democratic and Republican senators working to come up with a joint bill on the issue.

"The good news is, it seems like they are actually making progress. My expectation is that we will actually see a bill on the floor of the Senate next month," he said.

In a separate interview with Telemundo, Obama said Congress could pass legislation by this summer.

Immigration reform is a centerpiece of Obama's second-term agenda and would represent a substantial enhancement of his political legacy if he can get it passed.

Long-stalled immigration reform efforts gained momentum after the November elections, in which Obama won another term with overwhelming support from Hispanic voters for whom the issue is a motivating one.

Obama has courted Republican leaders on the issue and a group of senators from both parties is seeking to wrap up an agreement on a proposed law that would bring 11 million undocumented migrants out of the shadows.

The senators say their plan would offer a pathway to eventual citizenship, taking up to 13 years or more.

The plan would also include steps to better secure US borders and the introduction of an employee verification program.

But even if a plan passes the Senate, it must make its way through the House of Representatives, where majority Republicans oppose any solution that could be branded "amnesty" for illegal immigrations.

An Taoiseach Enda Kenny praised Mr. Obama's plans for reform when the two leaders met in Washington after St. Patrick's Day.