The United States has imposed a 12.5 per cent tariff on imports from Nigeria, saying the country has not effectively banned the importation of goods produced with forced labour.

The measure affects 60 economies and follows a U.S. trade investigation under Section 301 of the Trade Act.

The Office of the United States Trade Representative said countries that have adopted or pledged to enforce forced labour import bans will face a lower 10 per cent tariff.

The new duties exclude certain products, while U.S. officials say the policy is aimed at strengthening global efforts against forced labour.