"What is another day or two to get it right?" Tumahai asked.
"We could end up in the same situation again and how bad would that look? We need it right ... there's no second chance over this."
Madgwick said the original identification of sites by Ngāi Tahu for the TTPP had been "bang on".
"I don't want this problem apportioned to Ngāi Tahu. This is not our fault. The maps were bang on."
Cr Laura Coll-McLaughlin suggested an extension to the September 30 public submissions period to ensure everyone had time to see the map changes.
Poutini Ngāi Tahu worked to identify 216 areas and sites of significance across the West Coast over more than two years, but when the digital maps were transferred over to the planning team, some were distorted.
The mistakes only emerged when TTPP letters were sent to landowners last month, pointing out sites of significance to Māori had been identified on their properties, with rules taking "immediate legal effect".
It was news to some property owners, particularly at Kumara, near Gladstone and around Sawyers Creek in Greymouth.
"Unfortunately because of the speed which we were having to complete this [draft] work, there were some errors identified in the mapping," principal planner Lois Easton told the extraordinary plan committee meeting yesterday.
The system used to transfer the original maps meant some areas were completely wrong.
"The information passed over from Te Rūnanga o Ngāi Tahu has come over in our e-plans as different shapes. People have been identified under sites of significance to Māori which are not there," Easton said.
Legal advice was the mistakes and others could be dealt with by way of a "minor amendment".
This included heritage areas not "aligning" with the draft plan.
"That again is a minor amendment."
Easton said the distortion in the maps ranged from oval to ellipses.
"What that means is there are (maps) overlapping on to property that don't have a site, or the wrong part of the property."
The meeting agreed to look at a possible extension for submissions at its September 8 meeting.
Disclosure: Te Runanga o Makaawhio chairman Paul Madgwick is also the editor of the Greymouth Star. He took no part in the commissioning, writing or editing of this Local Democracy Reporting story.