Donald Trump will end his first year as president with the lowest approval ratings of any of his predecessors. A new poll gives Trump a 32% approval rating while 67% disapprove of the job done by the 45th US president.

The AP-NORC poll also found almost half (45%) of respondents thought Trump had broken campaign promises and overall his approval rating has fallen 10 points since March. The results come as Republicans work to get Trump's tax cuts through Congress before Christmas.

They amount to the biggest overhaul to the US tax system since the 1980s and amount, according to the president, to the biggest tax cut in history. "It'll be fantastic for the middle-income people and for jobs, most of all," Trump said.

"And I will say that because of what we've done with regulation and other things our economy is doing fantastically well, but it has another big step to go and it can't take that step unless we do the tax bill."

Trump's tax reforms will see the US corporate tax rate down to 21% from the current 35%. The top individual income tax will fall to 37% from 39.6%.

However, Democrats argue the tax plans will favour only the rich and offer little to the president's blue-collar base.

Since his inauguration in January, Trump attempted to roll back Obamacare, install a travel ban from mainly Muslim countries and extricated the US from the Paris climate agreement, Unesco and Trans Pacific trade agreement.

He has also faced continued pressure over Russian involvement in his election and suffered a set back when deep-Red Alabama voted for Democrat Doug Jones in its Senate election.

Supporters point to a growing economy and low unemployment as signs Trump is making a positive impact as well as his taking the fight to Muslim fundamentalist terror group Isis.