The US president is set to nominate Michael Mukasey, a retired federal judge, to replace Alberto Gonzales, the outgoing attorney-general, it has been reported.
Mukasey, whose official nomination is expected later on Monday, is considered a "law-and-order conservative" and an authority on national security issues.
Dana Perino, a White House spokeswoman, said in an email: "We are not commenting on any possible names for the attorney-general nomination."
But she also said in the email an announcement would be made "soon".
A senior Republican aide said that Mukasey came into consideration after Harry Reid, the senate Democratic leader, vowed last week to block a potential nominee, Theodore Olson, a former US solicitor general, on the grounds he was seen as being too partisan.
- Worked in federal prosecutor's office in New York, including under Rudy Giuliani, the current Republican presidential candidate and the city's ex-mayor.
- Nominated to the federal bench in 1987 by Ronald Reagan, then US president.
- Presided over case in which Omar Abdel Rahman, known as the "blind sheikh", and a dozen others were linked to the 1993 bombing of the US World Trade Centre.
Sources: Reuters, The Washington Post, The New York Times
Olson, who represented Bush in the US Supreme Court case that settled the contested 2000 presidential election, had been widely viewed as the top contender.
Charles Schumer, the Democratic senator who led the drive to force Gonzales out, said Mukasey has the potential to become a consensus nominee.
"While he is certainly conservative, judge Mukasey seems to be the kind of nominee who would put rule of law first and show independence from the White House," Schumer said in a statement.
"For sure, we'd want to ascertain his approach on such important and sensitive issues as wiretapping and the appointment of US attorneys, but he's a lot better than some of the other names mentioned."
Gonzales quit after both Democratic and Republican legislators challenged his truthfulness and ability to do his job as the head of US law enforcement.
Gonzales came under criticism for his dismissal last year of nine federal prosecutors and his handling of Bush's domestic spying programme, which has been criticised as unlawful.
Mukasey, appointed as a district judge for the southern district of New York, retired last year after nearly two decades of service.
He had earlier served as a federal prosecutor in New York.