TWEED Shire Council spent about $1 million re-routing the new Kirkwood Rd interchange around suspected Aboriginal artefacts.

Councillor Warren Polglase made the announcement at a Tweed Chamber of Commerce Business Breakfast last week, highlighting the cost of sustainable and culturally sensitive development.

Fill was taken from the right side of the motorway heading south to preload the construction site, but some rocks thought to be pieces of Aboriginal tools were discovered on a hill, blowing out the cost massively.

"It's the cost of heritage," Cr Polglase said.

"There would have been some cost involved anyway, but nowhere near the $1 million mark that it did cost.

"It blows out the whole construction process, but council has a responsibility to protect Aboriginal sites."

Cr Polglase said the "average Joe would probably say that it was a waste of money", but agreed that the re-routing was ethically the right thing to do.

Council's director of engineering Patrick Knight said it would have cost more to fully investigative the authenticity of the artefacts, rather than redesigning the interchange.

"It was ambiguous enough that we redesigned so the cutaway had a slope and formed more of a retaining wall," he said.

"To go through the process (of authentification) would have held up construction.

"Council is always conscious of issues like this."

Mr Knight said representatives of the Tweed Aboriginal community were informed of the artefact's discovery.

Similar artefacts are a rare find during construction in the Tweed, according to Mr Knight.

The artefacts were not removed from their position and remain untouched.

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