NDP Leader Jack Layton says his party could go to court to try to block the federal Conservative government from approving the sale of a key corporate part of the aerospace industry to U.S. interests.

"What we're doing is surveying all of the arguments and instruments that are available," Layton said in an interview in Ottawa on Sunday.

The main option being explored is whether it's possible to obtain a prohibition order from the courts that would prevent Ottawa — at least temporarily — from giving the go-ahead for the sale of the space technology division of Vancouver-based MacDonald, Dettwiler and Associates.

The proposed deal has come under fire from labour, environmental and public policy groups, who say it would gut the Canadian aerospace industry, cost the country jobs and lead to a loss of control over technology developed with the aid of millions of taxpayer dollars.

Layton said he has been consulting with critics of the sale — including the Canadian Auto Workers and the Rideau Institute for International Affairs — but was reluctant to go into detail about potential legal strategy.

"We're not ruling anything in or out at this stage," he said. "I don't want to step too far out on this because, needless to say, those who might oppose what we're doing might want to find out exactly what's in our playbook."

MDA wants to sell its space division, which developed the legendary Canadarm and the Radarsat-2 satellite, to Alliant Techsystems of Minneapolis, a major U.S. defence contractor. Alliant insists if the deal goes through, it will honour all of MDA's existing contracts with the Canadian government, including "access protocols" to Radarsat-2 in the event of a national emergency.

The $1.3-billion deal needs the approval of the federal government under the Investment Canada Act. Industry Minister Jim Prentice, who must rule on whether the transaction is of "net benefit" to Canada, bought some time by announcing March 20 that he would extend the deadline for a decision by 30 days.

He couldn't say exactly when the NDP will make a final call on whether to join in any court challenge to the sale. But he acknowledged that call will have to come soon, given the April deadline for action by Prentice.

"What is clear is that we need to move very quickly," said Layton. "It would have to be [done] in a very timely way."