Auckland Transport has sacked a senior manager amid an investigation into allegations of corruption over roading contracts.
The council body's chief executive, David Warburton, says the investigation has established "serious conflict of interest and performance issues" involving the official, whom it stood down on leave a month ago.
He said those came to light after an internal review of procurement and contract management procedures.
Invoices, contracts and other documents dating back to 2010, which is when Auckland Transport was established as a council-controlled organisation, were being reviewed.
A number of staff, supplier representatives and other stakeholders had also been interviewed.
External legal and forensic accounting advice had been sought, and the Serious Fraud Office and Audit NZ were being kept abreast of developments.
Dr Warburton said Auckland Transport remained uncertain how long its investigation would continue but expected to wrap it up "in weeks rather than months".
He said it was not in a position to say anything more, given potential future "employment issues" and legal proceedings.
In a previous statement, he said external forensic advice about Auckland Transport's road corridor maintenace operation had been sought from the PricewaterhouseCoopers consultancy.
PWC is also helping KiwiRail with separate allegations over irregularities over infrastructure contracts within its operation.
A Serious Fraud Office spokeswoman confirmed her organisation was still keeping a watching brief over the Auckland Transport investigation, but its involvement remained at that level at this stage.