Donald Trump's nominee to be attorney general, Pam Bondi, said she would not use the US Justice Department to target people based on their politics during her confirmation hearing on Wednesday.

"There will never be an enemies list within the Department of Justice," she told senators as she was repeatedly pressed on her loyalty to Trump. "I will not politicise that office."

But Bondi, who would become the nation's top law enforcement official if confirmed to the role by a Senate vote, did not directly rule out launching investigations into those the president-elect has clashed with.

"It would be irresponsible of me to make a commitment regarding anything," she said when asked whether she would investigate Jack Smith, who led two criminal cases against Trump.

Trump repeatedly threatened to investigate and potentially prosecute his political enemies during the election campaign.

Bondi, who is likely to be confirmed as the 87th US attorney general given the Republican majority in the chamber, stressed throughout the hearing that she would remain independent.

But she echoed Trump's view that federal prosecutions against him were political persecution, saying the department "had been weaponised for years and years and years".

Iowa Senator Chuck Grassley, a Republican, said the department had become "infected with political decision-making" and said it has been "weaponised" under the Biden administration, particularly against Trump.

These descriptions were repeated by other Republican members of the Senate Judiciary Committee and Bondi agreed with their assessment.

Questions from Democratic senators, meanwhile, focused on whether Bondi would say no to the president-elect.

"The concern is that weaponisation of the justice department may well occur under your tenure," Democrat Sheldon Whitehouse told Bondi. "We want to make sure that's not the case, that you remain independent."

They also focused a portion of their questioning on FBI director nominee Kash Patel who, if confirmed, would report to Bondi.

The FBI nominee has said he has an "enemies list" of people he will pursue if confirmed. Multiple senators asked Bondi about those comments, but she said she had not heard them and the justice department would not have such a list.

Bondi also told the committee that she would look at potential pardons of Capitol rioters on a "case by case basis" but added that she condemned "any violence on a law enforcement officer in this country".

The attorney general serves as the head of the Department of Justice, which enforces federal laws. If confirmed to the role, Bondi would give legal advice and opinions to the president and heads of executive departments.

Her confirmation vote has not yet been scheduled, but is expected in the coming days.

On Wednesday, Senators also quizzed Marco Rubio who is expected to be confirmed as Trump's secretary of state.

He warned that Washington must change course to avoid becoming more reliant on China and promised to overhaul US foreign policy to focus on American interests.