US President Donald Trump and wife Melania have tested postive for COVID-19.

Trump confirmed the news in a tweet on Friday evening (NZ time), saying he and the First Lady had returned positive test results.

"We will begin our quarantine and recovery process immediately. We will get through this TOGETHER."

US Vice-President Michael Pence has sent his and wife Karen's "love and prayers" to the couple, saying they were joining millions of other Americans in hoping for a full and swift recovery.

"God bless you President Trump and our wonderful First Lady Melania," he wrote.

The news comes just hours after Trump's top advisor, Hope Hicks, tested positive. Shortly after news of her result broke, the President announced he and Melania would enter quarantine. 

Hicks travels regularly with the President on Air Force One, and accompanied him to Cleveland for the presidential debate earlier this week alongside other senior aides.

The Centre for Disease Control recommends anyone who has been in contact with a confirmed case should isolate for 14 days.

The President is scheduled to participate in a second debate with Democrat opponent Joe Biden in Florida on October 15 - the future of which is now up in the air. 

He was also scheduled to appear at a number of rallies over the coming days, all of which will now be put on hold.