The road is being used as a bypass to the erosion-damaged portion of Beach Rd, between Oamaru and Kakanui.
There have been at least four crashes since traffic was diverted earlier this year.
In 2004, Sarb Investments Ltd was granted approval to subdivide land bordered by Beach, Thousand Acre and Gardiners Rds.
The company had to pay the council half the cost of upgrading Gardiners Rd as a consent condition.
Since the consents were issued, the matter of public safety, the vastly increased traffic on the road and the possibility it would become the link in keeping traffic moving along the coast, via Thousand Acre Rd, had "landed in the council's lap", Bill Brown, of Sarb Investments, said.
It left the council no option but to meet its original obligation under the two resource consents to fund the other half of the upgrade and "get on with the job", he said.
The developers had paid their share to the council and the council was now looking to avoid or ignore the matter.
He felt the council needed to be a "bit more honest" in its public statements about the cost of Gardiners Rd work and who should be paying.
Gardiners Rd resident Sheryl Leaman was aware of four crashes and had seen "a lot of near misses".
The council's roading assets manager, Gary Woock, said he would respond to Mr Brown but he did not necessarily want to do so through the newspaper.
A special sub-committee is looking at the coastal erosion issue and will make recommendations to the council.
