The U.S. Justice Department wants to know why the NCAA doesn't have a college football playoff system and says there are "serious questions" about whether the current format to determine a national champion complies with antitrust laws.

Critics who have urged the department to investigate the Bowl Championship Series contend it unfairly gives some schools preferential access to the title championship game and top-tier end-of-the-season bowl contents.

In a letter this week, the department's antitrust chief, Christine Varney, asked NCAA President Mark Emmert why a playoff system isn't used in football, unlike in other sports; what steps the Indianapolis-based NCAA has taken to create one; and whether Emmert thinks there are aspects of the BCS system that don't serve the interest of fans, schools and players.

"Your views would be relevant in helping us to determine the best course of action with regard to the BCS," she wrote.

"Serious questions continue to arise suggesting the current Bowl Championship Series system may not be conducted consistent with the competition principles expressed in the federal antitrust laws," Varney said.

Varney noted that the attorney general of Utah, Mark Shurtleff, has said he plans an antitrust lawsuit against the BCS, and that 21 professors recently wrote the department requesting an investigation.

Shurtleff, who met with department officials last fall to discuss a possible federal probe, said at the time that such an investigation was critical to the effort to get a playoff system.

The NCAA said Wednesday it would respond to the government's questions when it receives the letter.

Spokesman Bob Williams said Emmert consistently has said the NCAA is willing to move to a playoff format if schools with the nation's major football programs want to go that route.

Bill Hancock, the BCS executive director, was confident the current system complies with the law.

"Goodness gracious, with all that's going on in the world right now and with national and state budgets being what they are, it seems like a waste of taxpayers' money to have the government looking into how college football games are played," he said.

Under the BCS, the champions of six conferences have automatic bids to play in top-tier bowl games; other conferences don't. Those six conferences also receive more money than the other conferences.

Attorney General Eric Holder referenced Varney's letter at a Senate hearing Wednesday, in response to a statement from Sen. Orrin Hatch, a Utah Republican and BCS critic. Hatch called the BCS a "mess" and said that "privileged conferences" have tremendous advantages over the unprivileged.

"And I just hope that you'll continue to follow up on that particular issue," he said. "It's an important one, I think."

"I don't disagree with you," Holder responded. "You and I have talked about this issue, and I think I'm free to say that we have sent a letter to the NCAA about this issue and will be following up."

Before he was sworn in as president, Barack Obama said in 2008 that he was going to "to throw my weight around a little bit" to nudge college football toward a playoff system.