Seeka's chief executive Michael Franks denied the contractor was hired by Seeka at the time of the discovery but admitted the contractor had previously worked for the company.
He said the recent audit had detected "minor compliance issues and one visa anomaly" among the companies contractors. "In the case of the visa issue, the worker was employed by an independent contracting company, had a visa to work in New Zealand but I understand it was company specific in a different sector."
He could not comment on contractor performance outside Seeka but said the company had put steps in place to ensure contractors were compliant after the discovery of the illegal worker. The steps included giving contractors advice around employment contracts, payroll requirements, eligibility to work and safety, he said.
Mr Franks said the company had "no less than 10" government officials on site on May 12.
" ... overall we largely passed the audit with a couple of small corrective things to do. "Some other contractors have not passed and have been caught and, yes, people have been stood down."
Everyone who worked for Seeka had to be safety and employment accredited, he said.
The audit came to the attention of the Bay of Plenty Times after a contractor, who asked not be named, contacted the paper.