AUGUSTA — State Planning Office Director Darryl Brown is resigning effective Monday, the governor’s office has confirmed.

Brown, who was first appointed by Gov. Paul LePage as commissioner of the Department of Environmental Protection, was shifted to state planning when the attorney general determined he could not serve at DEP because of a conflict of interest. Brown owned Main-Land Development Consultants, an environmental consulting firm whose clients had been regulated by federal and state environmental agencies.

State law prohibits those who have received, in the two previous years, at least 10 percent of their income from clients who receive or apply for permits under the Clean Water Act, from serving as commissioner of DEP.

In his resignation letter, Brown said he’s accomplished his goal at State Planning, which was to eliminate the agency and move the functions to other parts of state government.

Last week, a working group in charge of designing a transition plan for the agency took a final vote, and will now forward its recommendations to the Legislature.

“Because of the Working Group’s affirmative action, my primary duties related to the State Planning Office have been completed,” Brown wrote. “Therefore, I am resigning as director of the State Planning Office effective Monday, Nov. 28, 2011.”