US President Donald Trump's former chief strategist Steve Bannon is being advised by Quinn Emanuel Urquhart & Sullivan, as he prepares to face investigators probing Russian meddling in the 2016 presidential campaign.

William Burck, the co-managing partner of Quinn's Washington DC office, is helping Bannon prepare for an interview with the House Intelligence Committee next week, according to the Daily Beast, which first reported the news.

A person familiar with the matter confirmed the representation but said Burck is advising Bannon only in relation to the House committee interview and his time on the presidential campaign. The representation does not extend to special counsel Robert Mueller's probe or to Bannon's transition to government and his White House service, the person said.

Burck, a leading white-collar and government investigations lawyer, is a former law clerk to Supreme Court Justice Anthony Kennedy and federal prosecutor who worked in the West Wing under President George W Bush.

He is also reportedly representing White House counsel Don McGahn and former White House chief of staff Reince Priebus in relation to the Russia investigation. He joined Quinn from Weil Gotshal & Manges in 2012.

Bannon has faced heavy criticism over his comments, calling a meeting between a Russian lawyer and Donald Trump Jr, Paul Manafort and Jared Kushner in June 2016 'treasonous' in the new Michael Wolff book on the Trump administration. The president responded by attacking Bannon and calling him "Sloppy Steve", which Bannon followed by walking back some of his earlier remarks.