Martin's Liberals reached "agreement in principle" Tuesday with the NDP that would see the New Democrats support the fragile minority government against efforts by the Conservatives and Bloc Quebecois to bring it down. The deal involves a guarantee of $4.6 billion in new investment in the environment, affordable housing, foreign aid, and post-secondary education and training.

NDP Leader Jack Layton had demanded that the Liberals eliminate $4.6 billion in proposed business tax cuts so the money could be spent on social programs. But the deal only calls for the tax cuts for big corporations to be put off.

Promised cuts for small-and medium-sized businesses will remain.

Martin called the deal "fiscally responsible" and "progressive."

"Under no circumstances will we go back into deficit," he said. "The fiscal integrity of this country . . . remains a fundamental element of our ability to finance social programs and our ability to create jobs.