The U.S. Justice Department could decide as early as Tuesday whether to approve North Carolina's new Republican-drawn voting districts or send them back for changes.

If they're approved, Democrats and a handful of independent groups are poised to challenge the districts in court. A prolonged court fight could delay N.C. elections in 2012, just as similar challenges did in 1998 and 2002. Previous challenges have resulted in redrawings.

States have to redraw districts every 10 years, after the census. In North Carolina, this is the first time in more than 100 years that districts have been redrawn while Republicans controlled both houses of the legislature.

Republicans are confident the Justice Department will approve, or "pre-clear," their new congressional and legislative voting districts.

"We're very optimistic about the feedback we've gotten," said Sen. Bob Rucho, a Matthews Republican who chairs the Senate Redistricting Committee. "I had an interview with Justice and (House) Chairman (David) Lewis had an interview and we felt very comfortable."

But critics of the plans are ready to go to court.

"We are gearing up for the long haul in terms of the battle," said Conen Morgan, a spokesman for the state Democratic Party. "We're not going to allow these maps to be upheld in court without a legal battle."

Both House and Senate Democrats are preparing lawsuits.

So are independent groups, led by the Durham-based Southern Coalition for Social Justice.

"I don't think it's any big secret that we're going to challenge the maps, the only secret is how we're going to challenge them," said Chris Ketchie, a policy analyst for the coalition.

Any challenges are likely to focus on two points.

The coalition and its allies are expected to argue that the GOP-written plans illegally segregate minority voters.

"Our organization is concerned about the way the plans are essentially segregating and promoting segregation of voters in ways not consistent with the Voting Rights Act," said Bob Hall, director of Democracy North Carolina, which plans to join a suit.

The party groups are also expected to argue about the number of split precincts and what they call the failure to observe "communities of interest."

"We feel we have very strong arguments for these," said Senate Minority Leader Martin Nesbitt, an Asheville Democrat.

Democrats have complained, for example, about the new Senate District 41 in Mecklenburg County.

The district runs from the Iredell County line in the north to Union County in the south. It takes in the three northern towns of Davidson, Cornelius and Huntersville as well as the southeastern towns of Mint Hill and Matthews.

At one point, the district narrows to two-fifths of a mile near the Cabarrus County line.

Rucho is confident that Republicans have created "fair, legal and now competitive districts."

"We're very optimistic we will see a pre-clearance," he said. "That is a rare occurrence in the redistricting world."