TORONTO -- Opposition politicians and environmental advocates are raising concerns about new legislation from the Ontario government that they say opens the door to development in a protected green space around Toronto.

Critics say the omnibus legislation aimed at cutting red tape for businesses contains clauses that could let municipalities override rules that protect the Greenbelt.

The 7,200-square-kilometre area that borders the Greater Golden Horseshoe area was established in 2005 to protect environmentally sensitive land from urban development.

Premier Doug Ford generated controversy during the spring election campaign when he initially pledged to open parts of the area to build housing -- a promise he backtracked on after facing intense criticism.

Economic Development Minister Todd Smith says the Progressive Conservative government has promised not to allow development in the Greenbelt and will keep that commitment.

But NDP legislator Catherine Fife says the legislation contains vague language that could allow for development in the area and Green party Leader Mike Schreiner says the bill puts established protections at risk.

"Despite explicitly promising to leave the Greenbelt intact, the Ford government introduced a bill yesterday that opens the Greenbelt to development," said Schreiner. "And not only the Greenbelt, it threatens hard fought for and valued protections for Clean Water, Great Lakes, Lake Simcoe and the Oak Ridges Moraine."

Fife said the "opaque" wording of the legislation was concerning.

"It leaves questions for people who are trying to maintain the law," she said. "I don't think this premier will be happy until he's paved over paradise and put up a parking lot."

The government said, however, that the legislation tabled on Thursday would only apply to municipal development of industrial land.

"We've made it very, very clear as the new government of Ontario that we are going to protect the Greenbelt," Smith said on Friday. "What this does though is give us the opportunity, in other areas, to ensure that when business wants to locate in Ontario ... that we have the tools to help them locate here quicker."

Under the proposed law, municipalities working on a specific project -- like attracting a major employer to the region -- can pass a by-law to request provincial approval to override certain regulations. Municipalities would have to provide a case to the government to warrant the override.

"The government would review the proposal and consider, among other things, whether there would be any impacts on public interests such as the environment or public health and safety," said Praveen Senthinathan, a spokesman for the ministry of municipal affairs.

"The ministry of municipal affairs and housing would work with partner ministries to consider potential impacts on matters of provincial interest, including protecting the Greenbelt."

Advocacy group Environmental Defence said the new legislation meant the current process to identify appropriate places for new development will be sidelined.

"The Greenbelt is the anchor of smart land-use in southern Ontario," said Tim Gray. "Opening it to development will set free rampant land speculation by developers, resulting in a loss of farmland and the disruption of farm communities."