NDP Leader Andrea Horwath hammered the Liberals on auto insurance rates Saturday, as she campaigned in the vote-rich Greater Toronto Area.

The New Democrats made in-roads in the region in the last election, gaining a toehold in a Brampton.

They're looking to expand that this time around, and Horwath's rally Saturday in the city was her second visit there this week.

She attacked scandals surrounding the Liberal government and talked up the NDP's plan to create jobs, but in a break from her stump speech dug into Premier Kathleen Wynne for not cutting auto insurance rates enough.

While the Liberals have cut rates, Horwath says they didn't go as low as promised and cited the case of a "Melinda" from Brampton who saw her rates rise.

Horwath says rates haven't dropped quickly enough despite the Liberal's budget pledge last year to drop them 15 per cent by August 2015.

Liberal attack ad

Wynne took a day off from campaigning Saturday but the Liberals were far from silent, rolling out a new attack ad. 

The ad takes aim at Horwath noting proposals for transit and social programs in the Liberal budget which Horwath said she would not support.

The 30-second spot, voiced by Wynne, is now online and will be broadcast on traditional media starting May 21, once a political advertising blackout ends.

Horwath's announced the NDP would not be voting for the budget, which sent Wynne to the lieutenant governor to ask him to dissolve the legislature and call an election.

Finance Minister Charles Sousa said at a press conference Horwath's decision raised the prospect of a "radical" Progressive Conservative government led by Tim Hudak.

Sousa criticized Hudak's plan, unveiled Friday, to cut 100,000 public sector jobs as a way to help eliminate the $12.5-billion deficit by 2016, saying it's contrary to his pledge to create jobs.