Canada is fighting back in the softwood lumber dispute by taking steps to levy C$200m in retaliatory sanctions against the US.

The Canadian government has submitted a request to the World Trade Organisation (WTO) for permission to impose a tariff surcharge on US imports.

But WTO permission may not be granted until it reviews US compliance to its original ruling, a process which could take until next summer.

Canada is also expected to file papers at the Court of International Trade in New York challenging the US commerce department’s claim that it has complied with WTO decisions relating to the calculation of the duties.

The commerce department reduced its countervailing duties by just 0.17% before Christmas by using a new calculation method. Canada had expected the 18.79% tariff to be slashed after WTO and North American Free Trade Agreement appeal panels rejected earlier US calculations.