Updated 9.51pm

US President-elect Donald Trump will appoint his son-in-law, Jared Kushner, to the position of senior adviser to the president, a transition official has said, a potentially thorny choice in the face of the country's anti-nepotism laws.

The appointment of Kushner, first reported by NBC, had been anticipated but it had been unclear what his official role would be. The New York Times and ABC also reported the upcoming appointment. 

Unlike Cabinet positions, the post would not require Senate confirmation.

Like Trump, Kushner is a New York-based real estate developer with a wide net of business dealings that could pose potential conflicts of interest.

Kushner, who married Trump's eldest daughter, Ivanka, in 2009, helped guide Republican Trump to victory over Democrat Hillary Clinton in the November 8 presidential election.

Kushner, 35, emerged as an important voice early in Trump's campaign and was involved in almost every aspect of it, from key personnel decisions to strategy and fundraising.

Kushner spearheads his family's real estate development company, Kushner Companies, and is the publisher of the New York Observer weekly newspaper, which he acquired at age 25.

It was unclear how any Kushner appointment would be affected by a federal anti-nepotism law that prohibits a president from hiring family members to serve in his administration.

Kushner is working with lawyers on how we would have to divest and distance himself from his family's business if he were to take a role in the Trump administration, the New York Times reported.

China's Anbang Insurance Group Co Ltd is in talks to invest in a project to redevelop a flagship New York City building owned by Kushner Companies.

The Times reported the deal on Saturday in an extensive article about Jared Kushner that detailed a November meeting between him and Anbang Chairman Wu Xiaohui just days after Trump was elected president.