Donald Trump has appointed former campaign manager Kellyanne Conway as counsellor to the president, one of his chief advisory positions.

In a statement, Mr Trump’s team said Ms Conway would be a close adviser and work with senior leadership to "effectively message and execute the administration’s legislative priorities and actions".

"Kellyanne Conway has been a trusted adviser and strategist who played a crucial role in my victory," said Mr Trump.

"She is a tireless and tenacious advocate of my agenda and has amazing insights on how to effectively communicate our message. I am pleased that she will be part of my senior team in the West Wing."

The appointment comes a week after Ms Conway turned down the role of press secretary, a role she was widely speculated to be given as she served as Mr Trump’s mouthpiece during the campaign.

She told radio host Hugh Hewitt last week that she "politely declined" the most visible role in the White House, leading to speculation she had declined a government role altogether.

“As you imagine in President Trump’s administration, communications will be a very important aspect for it and there will be a number of people handling that,” she added.

In the campaign statement regarding the new role, she thanked Mr Trump for the "amazing opportunity".

"A Trump presidency will bring real change to Washington and to Americans across this great nation. I am humbled and honoured to play a role in helping transform the movement he has led into a real agenda of action and results."

Ms Conway, although seen as one of the most reasonable and engaging figures in Mr Trump's team, has not been in the public spotlight without controversy.

She told PBS in 2013 that rape would not exist if women were "physiologically" as strong as men. When students questioned over how she, as a woman, could work for a man who had been accused dozens of times of sexual assault - which Mr trump denied - she accused the female student of trying to generate news headlines.

Kellyanne Conway accuses student of using sexual assault allegations to ‘try and make the news’

While most negative attention has been focused on Stephen Bannon, Mr Trump's chief adviser who founded a platform for white supremacists, Ms Conway has also lent her expertise in polling and strategising to anti-Muslim and extremist groups before she was appointed as Mr Trump's campaign manager.

Kellyanne Conway says Donald Trump’s team found 'an exception' in anti-nepotism law

A flawed poll from her company, The Polling Company, said 51 per cent of Muslims in the US said they believed they should have the choice to abide by Shariah law.

Mr Trump quoted this poll when first proposing to ban Muslims from the US last year.