A woman from the Democratic Republic of Congo who climbed up on the Statue of Liberty in New York and sat on the monument's base has been charged with trespassing.

Tourists were evacuated from Liberty Island in New York Harbour on Wednesday during a three-hour stand-off involving local and federal authorities.

She was identified as Therese Okoumou, a 44-year-old naturalised US citizen.

Ms Okoumou said she was protesting against President Trump's zero-tolerance policy on immigration.

She pleaded not guilty to charges of misdemeanour trespassing and disorderly conduct in a Manhattan court on Thursday.

Ms Okoumou, donning a T-shirt emblazoned with the words "White Supremacy is Terrorism", told reporters outside the courthouse that she scaled the landmark in an impromptu protest.

"When they go low, we go high and I went as high as I could," she said, quoting former First Lady Michelle Obama. "No children belong in a cage," she said.