Donald Trump is expected to tap a longtime advocate of greater protectionism as his US trade representative in yet another signal that his administration is poised to enact the aggressive trade policies he advocated during the campaign into government.

Robert Lighthizer, whose impending nomination was reported by US media on Monday, has been seen as the favourite for the trade role for weeks and has been leading the Trump transition team’s meetings with Obama administration trade officials.

He served as deputy US trade representative in the administration of Ronald Reagan at a time when the office was renowned for its trade battles with Japan and has long represented the US steel industry as a partner at law firm Skadden Arps.

As US trade representative, Mr Lighthizer would play a key role in delivering on Mr Trump’s campaign promises to crack down on unfair trading practices by China and to renegotiate the North American Free Trade Agreement with Canada and Mexico.

His appointment, which would have to be confirmed by Congress, would be the latest signal of what is likely to be a major shift in US trade policy when Mr Trump takes office on January 20.

The incoming Republican president has already vowed to pull the US out of the Trans-Pacific Partnership, a vast Asia-Pacific trade deal negotiated by President Barack Obama. He also has threatened to impose punitive tariffs on China in what some fear could become the trigger for a trade war between the world’s two largest economies.

Mr Lighthizer, who served as treasurer of Bob Dole’s ill-fated 1996 run for president, would be the latest prominent trade hawk to join the Trump administration.

The president-elect before Christmas named Peter Navarro, an economist and author of a book entitled “Death by China”, to lead a new National Trade Council within the White House. He also has nominated billionaire investor Wilbur Ross to serve as commerce secretary, a role from which he is expected to guide the administration’s trade policy.

Some analysts have raised questions over whether the creation of the new trade council and Mr Ross’s expected leadership on trade will result in a diminished role for the US trade representative, a role that in the past has served as presidents’ trade tsar. But Sean Spicer, Mr Trump’s spokesman, said in recent days that the USTR would continue to be the US’s lead trade negotiator and would only be guided by Mr Ross and the trade council.

In recent years Mr Lighthizer has been a leading advocate for a more muscular approach to trade among ideological conservatives, arguing for what has been the pro-trade Republican party to embrace protectionism.

“Modern free traders . . . embrace their ideal with a passion that makes Robespierre seem prudent,” Mr Lighthizer wrote in a 2008 New York Times op-ed.

“They embrace unbridled free trade, even as it helps China become a superpower. They see only bright lines, even when it means bowing to the whims of anti-American bureaucrats at the World Trade Organisation . . . They see nothing but dogma — no matter how many jobs are lost, how high the trade deficit rises or how low the dollar falls.”

Although he has in recent years outsourced production of Trump-branded products overseas, the incoming president has in books and other forums long been an advocate for a tougher US trade policy. That drew the notice and backing of Mr Lighthizer.

In a 2011 column written years before Mr Trump’s run for president, Mr Lighthizer likened the reality TV star’s approach to trade to that of Alexander Hamilton and Ronald Reagan and said it was an example Republicans should follow.

“The recent blind faith some Republicans have shown toward free trade actually represents more of an aberration than a hallmark of true American conservatism,” Mr Lighthizer wrote then. “It’s an anomaly that may well demand re-examination.”