Saskatchewan Premier Brad Wall says the hostile takeover bid from BHP Billiton for PotashCorp should kick-start a debate about how the federal government approves foreign investment in Canada.

Industry Minister Tony Clement is expected to announce his decision on the Anglo-Australian company's US$38.6 billion bid sometime this week, perhaps as early as Wednesday.

On Sunday, Wall said because Saskatchewan is home to 53 per cent of the world's potash reserves, and as much as 30 per cent of that is "at play in this deal," the government should consider the benefits to Canada of keeping a "Canadian corporate champion in the area."

"Maybe this augers in a new era where we will have a look at these investment takeover proposals through a different lens," Wall told CTV's Question Period in an interview from Toronto. "We want to welcome foreign direct investment, but there may be some that are so big and so strategic that we have to be circumspect, and I don't think that's a bad exercise to go through as a country."

Potash is a valuable resource that is made into fertilizer, which is essential for growing crops. Potash is in high demand around the world, but particularly in countries such as India and China, Wall said.

After weeks of publicly voicing his opposition to the deal, saying the province could lose as much as $6 billion and countless jobs, Wall announced his government's official position about 10 days ago. Wall told the Regina and District Chamber of Commerce that his government "must say no to this hostile takeover."

Provincial and federal politicians of all political stripes have professed their support for Wall's position, including Alberta's Conservative Premier Ed Stelmach, Quebec's Liberal Premier Jean Charest and Manitoba's NDP Premier Greg Selinger.

Federal NDP Leader Jack Layton has put forward a motion in the House of Commons calling on the Conservatives to block the bid.

The decision is ultimately up to the federal government, which must weigh the net benefits to Canada of a foreign takeover according to criteria set out in the Canada Investment Act.

NDP MP Paul Dewar said the act should be updated to better protect valuable Canadian commodities, which are attractive to foreign companies.

"It used to be we were hewers of wood, drawers of water, that was our Canadian motto," Dewar told Question Period. "Now it's hewers of wood, drawers of water, but for whom? It used to be for Canadians. Now we are seeing these takeovers happen and they're being done for basically these hedge funds and others that come in and raid the cupboard and invest as if they're going to improve things and they don't."

Conservative MP Mike Lake said the Act cannot be changed dramatically because of Canada's existing trade agreements.

But he told Question Period the government's decision on PotashCorp "is going to be taken with the net benefit to Canada in mind."

Wall said should the deal go through, the loss of revenue to the province would be "pretty significant."

"That's the difference between a balanced budget and a deficit budget," Wall said. "That's the difference between lower taxes and not being able to lower taxes and not being able to reduce debt."

And Wall was adamant that the company will not return to government hands if BHP's bid is ultimately rejected.

"When it was a Crown corporation, it lost money, it lost a lot of money. And it wasn't very good at creating jobs because government, it may be good at some things, but running a fertilizer company ain't one of them," Wall said.

"Since it's become privatized, there's been a massive expansion in the number of jobs and investments in the province, and we make more money today as a provincial government off royalties and taxation from the PotashCorp when we ever did when it was a Crown corporation."