WASHINGTON (Reuters) - President Barack Obama is forging ahead on a wide-ranging plan to overhaul the U.S. immigration system early this year, including a path to citizenship for illegal immigrants already in the country, the New York Times reported on Sunday.

Obama wants to advance the plan even as he faces tough battles with Congress over fiscal issues and gun-control laws, and may lay out his ideas during his annual State of the Union address on February 12, the Times said, citing senior administration officials and lawmakers.

The president had made immigration reform a key promise for his second term, and said in November after he won the election that he expected a bill would be introduced in Congress shortly after his January inauguration.

"We are still assessing our options, no decisions have been finalized and as a result it would be premature to speculate - reports to the contrary are inaccurate," a senior administration official told Reuters on Sunday.

The Times said the immigration plan would require immigrants seeking to obtain legal status to pay fines and back-taxes, and would make it possible to pursue citizenship.

The plan would require businesses to verify that new employees are in the country legally, and could create a guest-worker program for low-wage immigrants, the report said.

It may also add visas to relieve backlogs and allow high-skilled immigrants to stay in the country, the Times said.

Some analysts had expected that Obama's immigration reform plans could be delayed by fractious deficit talks with Congress, which face a series of critical deadlines in February and March.

Obama will need cooperation from Republicans, but they have acknowledged they need to address issues important to Latinos, an influential voting bloc that voted heavily for Obama and his Democrats in the November election.

Top Republican lawmaker John Boehner has said he wants to see immigration reforms. The House of Representatives passed a bill in November that would create a permanent visa program for foreigners with advanced science and technical degrees.

The Times said a bipartisan group of senators led by Charles Schumer, a New York Democrat, and Lindsey Graham, a South Carolina Republican, would like to introduce comprehensive legislation as early as March, and hold a vote by August.

"This is so important now to both parties that neither the fiscal cliff nor guns will get in the way," Schumer told the Times, saying talks were advancing quickly.

Senator Marco Rubio of Florida, often mentioned as a future Republican candidate for president, is also working on the issue, but has proposed tackling the issues in stages rather than in one comprehensive law.

His plan would allow illegal immigrants to gain temporary status and eventually apply for permanent residency, Rubio told the Wall Street Journal in an interview published on Saturday.

Los Angeles Mayor Antonio Villaraigosa, a rising star in the Democratic Party, is slated to speak in Washington on Monday on the importance of quickly advancing immigration reform.

"We can't do this piecemeal, and we can't have second-class citizenship. This has to be a pathway to full citizenship," Villaraigosa said on the CBS show "Face the Nation" on Sunday.