Ontario Green Party Leader Mike Schreiner says his party is in the midst of its biggest campaign ever with a target of winning no less than a seat at Queen's Park.

"Our goal is to at least break through in one riding, establish a beachhead from which we can grow the party in addition to driving a policy agenda," Schreiner said during a press conference on Friday.

The Greens have never held a seat at Queen's Park but is pushing itself into the political mainstream by demanding inclusion at an upcoming debate between party leaders.

The debate, set for Sept. 27, will be the only head-to-head meeting between Liberal Leader Dalton McGuinty, PC Leader Tim Hudak and NDP Leader Andrea Horwath before the Oct. 6 vote.

Schreiner says he deserves a seat at the table as well and hasn't ruled out legal action if he isn't included. The broadcast consortium has argued that the party should not be invited to the debate because it does not hold a seat in parliament.

Federal Green Party Leader Elizabeth May called for Schreiner's inclusion as well, saying each party should have an even foothold.

"In a democracy there are no seats in the House at the time of the debates. Everybody's running for a position," she told reporters on Friday.

For the first time ever, the Green party had a candidate running in each of the province's 107 ridings before the writ was dropped this month.

Schreiner suggested his party was trying to emulate its federal counterparts this election, which saw May become the first elected Green party representative in Ottawa. He says winning five seats is not outside the realm of possibility.

The Greens say they are currently polling second in two ridings including Dufferin-Caledon, where the Greens placed second in the last federal election, and Guelph.

"We're running a strong third in a number of other ridings that I think could catapult us up into first, potentially," Schreiner said.

The Ontario Greens earned 8.4 per cent of the vote in the last provincial election.

This time around, the Ontario Greens are campaigning on the promise to create good local jobs, invest in energy efficiency and conservation and ensuring sustainability of the health care system.

With files from CTV Toronto's Natalie Johnson. Follow her on Twitter at @NatalieCTV.