Andrea Horwath used her first day on the job as Ontario's new New Democratic Party leader on Monday to grill the government over the thousands of people in the province who have lost theirs.

Horwath, who was named this weekend to replace Howard Hampton at the party's helm, received a standing ovation from MPPs to mark the first time a female politician has taken the NDP leader's seat at Queen's Park.

Premier Dalton McGuinty was the first to walk across the floor to shake Horwath's hand and offer his congratulations. He was followed by all his ministers and members of the other parties.

Horwath used her first question to ask McGuinty why he hasn't done more to help the province's struggling workers.

"These workers and their families, premier, are scared," she told the legislature. "With all of the tools that this government has at hand and has at its disposal, how could the premier let this happen?"

McGuinty replied that his government has been working to create jobs and will continue to do so.

Horwath has pledged an NDP government would replace the close to 200,000 manufacturing jobs the province has lost since 2004, as well as offer hard-hit industries a break on their electricity costs to help companies combat the losses.

Horwath also used her first speech as party leader to promise to bring in public and affordable child-care and increase the minimum wage.

'Far removed' from Rae era, new leader says

The New Democratic Party has just 10 seats in the 107-seat provincial legislature.

Horwath, a 46-year-old former Hamilton city councillor and community organizer, has only been at Queen's Park for slightly more than four years.

But she has promised to rebrand and refresh the provincial NDP, which still hasn't recovered from the crushing defeat of the Bob Rae government in the mid-1990s.

"Certainly, I am far removed … from the time we were in government," she told CBC News.

Graham White, a political scientist from the University of Toronto, says Horwath may be a new leader, but her promise to replace the lost manufacturing jobs is a sign the NDP still needs new ideas.

"We are seeing a fundamental change in the Ontario economy, and this party and the province need to move on and do something different," White told CBC News.

New Democrat MPP Peter Kormos, who supported Horwath, insisted there have to be changes inside the party, not just at the top.

"There's faces that have been around far too long who are far beyond their expiry dates," Kormos said. "Time for these folks to move on."

With files from John McGrath and the Canadian Press