The comment comes amid reports Swiss commodities trader Glencore and U.S. agribusiness Cargill are possible bidders for grain handler Viterra (TSX:VT).
NDP Leader John Nilson says the issue for Canada is about who controls the flow of grains and oilseeds.
He says control is lost if every company that farmers sell grain to is foreign owned.
Nilson also says the Saskatchewan government should have been thinking about this potential situation with the end of the Canadian Wheat Board's marketing monopoly.
Premier Brad Wall says Viterra does not fit Saskatchewan's definition of a strategic resource, but he says there are also fiscal and economic impacts to consider in a potential takeover.