Premier Christy Clark and other provincial and territorial leaders have written to Prime Minister Justin Trudeau, asking him to refute the latest lumber trade action by U.S. interests.

"Unfair and inaccurate allegations of Canadian lumber subsidies" have been made by 25 U.S. Senators to U.S. Trade Representative Michael Froman, seeking a reduction in the cap on Canadian lumber sales, the premiers wrote from their meeting in Whitehorse this week.

The premiers cited decisions by the World Trade Organization and NAFTA in 2006 that found Canadian subsidies to be less than one per cent and ineligible for trade action.

Trudeau and U.S. President Barack Obama reported progress on negotiating a new softwood lumber deal after their meeting in Ottawa in late June.

Trudeau and Obama's joint statement acknowledged the increase in cross-border ownership of forest products producers, and said a key feature a new agreement would be "designed to maintain Canadian exports at or below an agreed US. market share to be negotiated."

The last Canada-U.S. softwood lumber agreement expired in the fall of 2015, leaving trade unrestricted as Canadian producers benefit from a stronger U.S. dollar and housing construction.