Under the 26 council system applications to build a new house or erect an extension went through Stormont's environment department.
Councils will be now able to accept or reject certain developments in their own areas.
Tom Frawley has said he is concerned a loophole has been left open.
Speaking to BBC Radio Foyle's Breakfast programme, Mr Frawley said he was worried councillors whose parties receive large donations from property developers do not have to declare them before making decisions on their planning applications.
"We have still this issue in Northern Ireland where parties do not maintain registries of who are donating money to them, and I think that's the issue that concerns me. It's outside of my control.
"I think if we want the trust and confidence that is essential in decision-making of the new local councils, that particular gap needs to be narrowed or filled," Mr Frawley added.
Councillors comply to a code of conduct when they take up their role.
The code says councillors should not act in order to gain financial or material benefits for themselves, their families, friends or associates when conducting council business.
They should also always act in the public interest.
The Northern Ireland Ombudsman has warned the transfer of planning powers to the new 11 super councils could make corruption easier.