NDP Leader Tom Mulcair promised to give the sagging manufacturing sector a boost by delivering an innovation tax credit worth $40 million.

"The manufacturing industry helped Canada's middle class, however over the last 15 years, this important sector has been hit hard by job losses," he said during a campaign stop in London, Ont. "Consecutive Liberal and Conservative governments have sat on the sidelines while half a million manufacturing jobs disappear."

The credits would defray costs of machinery, equipment and property to assist research and development in the manufacturing sector.

Mulcair has been hammering Conservative Leader Stephen Harper for focusing on the oil and gas sector at the expense of thousands of jobs in manufacturing.

The economy has emerged as the key campaign issue this week, as a Chinese market meltdown sparked global volatility. 

Mulcair defended his plan to balance the books amid the uncertainty, insisting his priorities are different than the other parties. 

If elected Oct. 19, the NDP would scrap the Conservative income-splitting plan and raise corporate tax rates to finance a new child-care program and more breaks for manufacturing and small business.

"Our choices will be very different from Mr. Harper's. We will not be running a deficit," he said.