Christina Friederika Müller was thrown out of the country along with two French activists earlier this month, a decision which has infuriated the president, according to news agency AFP.
They do not deserve to be extradited, but should have been brought before a court, and “stuck in prison,” he said.
Colombian authorities accused Müller of taking part in demonstrations held by striking sugar cane workers in the south western city of Cali. The demonstrations turned violent, with fighting between the strikers and police, but Müller's colleagues say she did not participate but was simply arrested in the street.
She had been invited to the country by a number of non-governmental organisations belonging to the Network of Solidarity and Friendship with Colombia, to investigate alleged abuses of human rights.
Activists say she was arrested without a warrant, held incommunicado for a night, and refused permission to have access to a lawyer while being questioned.
She has been told she will not be allowed back into the country for seven years.