US President Donald Trump's assertion that he had heard Ireland was going to cut its already low corporate tax rate is "fake news", Taoiseach Leo Varadkar has said.

Mr Trump raised a few eyebrows on Monday when he told reporters at the White House: "I hear that Ireland is going to be reducing their corporate rates down to 8% from 12%."

"I can confirm that President Trump's claim that we are proposing to reduce our corporation profit tax to 8% is indeed fake news. There is no such plan to do so," Mr Varadkar told the Dáil in answer to a question from Solidarity PBP TD Richard Boyd Barrett on Mr Trump's comments.

The 12.5% corporate tax rate has long made Ireland a hub for investment from major US multinationals such as Google and Facebook and a target for criticism from US politicians.

The Government has responded by consistently stressing that the corporate tax rate will neither go up nor down and the rate was reaffirmed just last week in Budget 2018.

"Our corporate profit tax is 12.5%, has been for a very long time through changes of government, through recessions and through periods of growth, and it as much that certainty that is as important to business as anything else," Mr Varadkar said.

Mr Trump has said he would like to see the US corporate income tax rate reduced to 20% from 35%, in part to better compete with lower tax jurisdictions such as Ireland.