NEW YORK (AFP) - US President-elect Donald Trump sat down Wednesday with top tech executives - including several of his sharpest critics - to mend fences after a divisive election in which the majority of Silicon Valley backed Hillary Clinton.

The afternoon summit at Trump Tower comes as the 70-year-old Republican leader-in-waiting continues to fill out his cabinet, with former Texas governor Rick Perry tapped to serve as secretary of energy.

Washington is still buzzing over Trump's nomination of ExxonMobil CEO Rex Tillerson to be his secretary of state, with concerns about the oilman's ties to Moscow riling some amid allegations of Russian interference in the Nov 8 election.

Against that background, Trump is heading into hostile territory - with the exception of PayPal co-founder Peter Thiel, Silicon Valley shunned the New York billionaire during the presidential campaign, throwing their weight behind his Democratic rival Clinton.

"I'm here to help you folks," Trump said at the start of the meeting. "We want you to keep going with the incredible innovation. There's nobody like you in the world."

Trump and Vice President-elect Mike Pence were seated at a long table with America's top tech titans, including CEOs Tim Cook of Apple, Satya Nadella of Microsoft, Larry Page of Alphabet (Google) and Brian Krzanich of Intel. Also on the guest list were Amazon founder and chief Jeff Bezos, Tesla and SpaceX founder Elon Musk, Facebook's chief operating officer Sheryl Sandberg and Oracle chief executive Safra Catz.

Trump's three adult children Don Jr, Ivanka and Eric were also present.

One major absence was that of Twitter CEO Jack Dorsey - despite the fact that the billionaire-turned-president-elect uses the social network as a major means of getting out his message.

Bezos has been the target of the Manhattan real estate tycoon's ire, for allegedly using The Washington Post to secure tax benefits for Amazon - and to attack the Republican. Bezos responded by cheekily offering Trump a trip into space - on a rocket operated by his Blue Origin space flight company.

Late last month, a group of 17 tech associations offered to work with Trump while calling for policies to "foster growth and innovation." .

The effects of a Trump presidency on the sector are hard to foresee. While the tech industry is likely to oppose any trade barriers or efforts to limit immigration, many companies are expected to welcome a lowering of corporate tax rates promised by Trump, especially on profits repatriated from overseas.

"We're going to make fair trade deals. We're going to make it a lot easier for you to trade across borders. There's a lot of restrictions, a lot of problems that I think you see," Trump told the executives at the start of the meeting.

Tech firms led by Apple are responsible for the lion's share of an estimated us$2.5 trillion being held overseas by US companies, and are reluctant to bring those funds back and face a hefty tax bill.

A potential clash between Trump and the sector is possible over encryption, and the ability of law enforcement and intelligence services to decrypt devices for national security investigations.

Trump said Wednesday he would add Musk and Uber CEO Travis Kalanick to join his advisory council of business leaders.

"My administration is going to work together with the private sector to improve the business climate and make it attractive for firms to create new jobs across the United States from Silicon Valley to the heartland," Trump said.

Trump is now putting the finishing touches to his cabinet, formalising his nomination of Perry and reportedly choosing Montana Representative Ryan Zinke to be his interior secretary.

The nomination puts Perry, the oil-rich state's longest-serving governor, in charge of a vast array of energy oversight, including maintenance of the US nuclear weapons arsenal, enhancement of nuclear security and science and innovation in the energy field.

"As the governor of Texas, Rick Perry created a business climate that produced millions of new jobs and lower energy prices in his state, and he will bring that same approach to our entire country as secretary of energy," Trump said in a statement.

Perry, who participated in the Republican primary but was crushed by Trump early on, once assailed him as a "cancer on conservatism."

On Wednesday, Forbes magazine ranked Trump as the second most powerful person of the year - right behind Russian President Vladimir Putin.