A $180 million accounting error at the Ministry of Transport last year was not discovered for six months, and eventually led to the resignation of one worker.
Ministry chief executive Martin Matthews revealed details about the mistake at a parliamentary committee hearing this morning, saying the matter had been dealt with with the "utmost seriousness".
The error occurred when a figure was left out while data was being transferred between spreadsheets, leaving the New Zealand Transport Agency (NZTA) apparently up $180m.
"The effect of that error was that for a period of time the NZTA believed it had more money in the bank than it did," Mr Matthews said.
"Both the NZTA and and we took this extremely seriously ... The staff member who made the accounting error took it so seriously that he resigned and has left the ministry."