Eurobodalla Shire Council has called for owners and builders to comply with development conditions, after a recent $6000 on-the-spot fine to a developer for unauthorised earthworks.
The council said there was also a spate of illegal development involving tiny houses, demountables, cabins, and shipping containers in the past year.
Council environmental services manager Deb Lenson said placement of structures on land required development consent in the majority of circumstances.
"That includes obvious things like buildings, swimming pools and retaining walls, and we also strongly recommend contacting council for advice prior to buying a shipping container, cabin or a tiny house," Ms Lenson said.
"You might think, 'it's only small and it's my land', but structures like these can impact the environment and your neighbours.
"That's why terms and conditions are connected to development consents and why all councils take them so seriously."
Ms Lenson said on-the-spot fines ranged from $1500 for an individual to $6000 for a corporation for illegal development.
Orders could also be made to restore the site or demolish unauthorised work.
"Significant breaches may be pursued through the courts resulting in fines up to $1.1 million for a corporation," she said.
"Everyone involved in the illegal development may be held accountable and that includes owners, contractors, company directors, even employees.
"Our advice is err on the side of caution and ask for council's assistance early on."
The council said it had a development help desk to provide guidance on preparing applications.
Informal meetings at the council's main office could be arranged with planning staff to provide general advice prior to lodgement of a development application.
A formal Development Application Pre-Lodgement Panel service was available for larger developments.
Call the development help desk on 4474 1231.