LUSAKA, March 6 (Xinhua) -- Immigration authorities in Zambia have arrested 41 Ugandan herbalists for unlawful stay in the country, a spokesperson said on Tuesday.

The Ugandan herbalists were arrested on Sunday at a lodge in Lusaka, the country's capital where they had gathered to elect leaders of their illegal association of Ugandan herbalists, Namati Nshinka, Immigration Department Spokesperson said.

The spokesperson added that all the 41 Ugandan herbalists failed to produce travel or immigration documentation at the time of arrest and have since been detained.

Zambia, he said, has witnessed an upswing in the number of foreign nationals trading in herbal products, most of which have not been tested and certified safe by competent authorities.