PORTLAND — A lawyer for Maine’s Land Use Regulation Commission says the agency had broad discretion in approving a massive development in the Moosehead Lake region, but lawyers for environmental groups say the panel shouldn’t have tweaked the plan without reopening the proceedings.

Maine’s highest court heard arguments today in a case that prompted criticism from Gov. Paul LePage, who said the permitting process should not be allowed to continue for years and years.

It appears that the process will continue at least for a few more months.

Plum Creek’s plan calls for 821 house lots and two resorts with more than 1,200 housing units at Big Moose Mountain and Lilly Bay. It was approved in September 2009, nearly five years after the Seattle company announced plans to rezone nearly 400,000 acres.