The panel met in Cromwell on Tuesday to hear an application from Paul and Emily Robertson to subdivide their property into lots of 2ha and 2.7ha.
The land is designated rural resource area under the district plan, which sets minimum lot sizes of a 2ha minimum and 8ha average.
The couple outlined their plans for the site, which was to move from their existing home and build a new house on the larger lot.
Panel chairman Neil Gillespie said the issue was not about what the couple were trying to achieve but the "wider picture" in terms of compliance.
Council senior planning officer Oli Monthule-McIntosh told the hearing granting the application would amount to a "plan change by stealth" and his recommendation was to decline it.
Speaking to her submission against the application, Environmental Services consultant Kate Wardle said the Queensberry area was at a "tipping point".
That was based on lot sizes and a lack of assessment of biodiversity, and it contributed to climate change by allowing people to live further from their places of work.
Mr Robertson said they had already adopted many of Ms Wardle’s environmental considerations, including extensive planting of most of the native species she recommended.
He had carefully sought and obtained the agreement of all owners of neighbouring properties and had waited a year to speak to one based in Texas, he said.
The panel reserved its decision.
