A soon-to-be ratified investment treaty between Canada and China has the potential to wrest control of natural resources away from the provinces, the leader of the federal NDP said Tuesday.

"I think one of the things that we have to know is that this can cause huge upheaval in the province's ability to control their natural resources and real problems for Canada's sovereignty long-term," Tom Mulcair said in an interview with The Canadian Press.

Control over resources is a particularly prickly topic in Alberta, where Mulcair was making a stop to support anti-poverty advocate Dan Meades, the party's candidate for Calgary-Centre in a Nov. 26 byelection.

Mulcair has said previously that a New Democrat government would do anything in its power to extricate Canada from the Foreign Investment Promotion and Protection Agreement if it's found to not be in the country's best interest.

"I think the average Calgarian and the average Albertan understands very well that the battles that were fought 30 some-odd years ago to get control of natural resources put in the constitution shouldn't be thrown aside easily," Mulcair said at Meades' campaign headquarters, where volunteers were busily working the phones in the next room.

"People are starting to realize that this could play havoc with the province's ability to control their resources going forward."