A planing proposal to amend the Dubbo Local Environmental Plan (LEP) 2011 to increase the maximum floor area of a secondary dwelling to 65 per cent of the primary dwelling was adopted at the May ordinary meeting of council.

Council consulted with the Department of Primary Industries (Agriculture), NSW Rural Fire Service and the Office of Environment and Heritage (OEH).

OEH had no specific comments to make on the proposed amendment, while the other organisations said they had no concerns.

It's been almost 12 month since the issue was first raised at the former Dubbo City Council.

In July last year then-councillor Greg Matthews called the 40 per cent secondary dwelling size a "mistake" in the city's LEP.

"If you have the good fortune of living in Parkes you'd have a 60 per cent ratio, if you lived in Orange it would be 50 per cent. If you lived in Brewarrina it'd be 80 per cent and you could build a 177 square metre property and be fine," he said.

"If you've got a really big place, then you can build a big place beside it. If you've got a normal-sized 220 metre-squared home than you have to build a shoebox. I just doesn't seem to be logical."

Western Plains Regional Council will now request the Department of Planning and Environment prepare a draft amendment to the LEP.