ABC Photosigns associate Bill Matheson said in a submission supported by the Harcourts real estate firm that the panel should adopt more generous sign dimensions from the former Manukau City Council.
Auckland Council staff want to restrict residential property sale signs to 1.8sq m and to limit their height to 2m.
Mr Matheson said Manukau's allowances - described in council documentation as 2.5sq m for signs up to 2.5m high - followed efforts by that body to involve the industry and to survey residents.
He and others were also concerned at a proposed requirement for signs along bus routes to be set back by 0.8m from road edges.
A lawyer for six business organisations, Grant Hewison, said a 0.8m clearance might be appropriate at bus stops for the safety of passengers, but extending it along entire routes would be "unnecessary and problematic".
The council is proposing a tighter restriction, of 0.33sq m, for signs advertising sexual services in residential areas, a third of the size now allowed in the former Manukau City and Franklin district.
But such signs have previously been prohibited in residential areas in some areas and Dr Hewison said the public was probably not aware of the proposal to allow them.
Smith & Caughey's department store executive Terry Cornelius said a restriction on the size of advertising on shop-front windows to 25 per cent of their height or width could ruin his store's Christmas preparations.
That was because the Queen St store covered its windows with signs, enabling staff to prepare Christmas displays behind them, away from the gaze of small children.
"Under the bylaw, we will not be allowed to do that."