Rouge Park will become Canada's first urban national park. (Rouge Park)

A dispute has surfaced over the boundaries of what will soon become the GTA's first national park.

In its Throne Speech in June, the Conservative government pledged to designate Rouge Park as Canada's first urban national park.

With wetlands and meadowlands the park is just east of Toronto, nestled between Markham and Pickering.

It is a dream come true for some environmentalists who have been lobbying for the national park designation for more than a quarter of a century. 

"If we don't protect this park," said Jim Robb, a member of the Friends of the Rouge Watershed, "developers will try to get a hold of it in some way."

But now Robb and others are asking for an additional 57 square kilometers of federally owned farm land on the northern boundary to be included as part of the park.

Farmers like Mike Whittamore are calling it a land grab.

"In the last 20 years, they've come north of Steeles [Avenue], gone up the valley corridor and they continue to expand their area asking for more and more and more," said Whittamore.

The government took control of Whittamore's land in the 1970s.

Since that time he has been renting it back, with the hope that one day he will be allowed to buy it. 

But if the park expansion goes through that is unlikely to happen.

It's a case of competing interests with one side saying they want to maintain the ecological integrity of the land while farmers say they just want the security of ownership.

The 12-member group that will manage the new park has proposed an extension of the boundary, just not as far as the Friends of the Rouge Watershed want.

"About half of Rouge Park is currently farm land," said Alan Wells, one of the group members, "and we intend on keeping it that way."

The federal government has the final say and the first of many official planning meetings is happening later this month.