New Zealand's Treasury department says an error on its website allowed highly sensitive government budget information to be accessed by the public ahead of time, after earlier suggestions there had been an illegal hack.
The Treasury this week said its website had been "attacked" 2000 times and that it believed it had been "deliberately and systematically hacked", after the country's centre-right National Party released details from the Labour-led administration's upcoming national accounts.
But on Thursday the department revealed a problem with a test website had meant some details from the budget could be searched on its main website using the correct phrases.
Police had dropped their probe into the leaks because it did not appear to be illegal, Treasury said.
The allegations have led to furore in New Zealand's parliament and threatened to overshadow Thursday's release of the Ardern's government's much-touted "wellbeing budget".
The new style of government book-keeping aims to add social measures such as mental health and child poverty to traditional economic indicators and has been a cornerstone of the administration's work.
Hours ahead of its launch, opposition leader Simon Bridges held a press conference calling for the resignation of Finance Minister Grant Robertson and Treasury head Gabriel Makhlouf for what he said had been deception and smears.
"Treasury has known since Tuesday exactly what happened and they covered it up to hide their incompetence," Bridges told reporters.
He also played a video recreating how the information had been found simply using a search bar on Treasury's front page and said the party had simply "stumbled" across the information.
In a statement, Makhlouf said three computers, including one in parliament, had made 2000 searches of the site over two days and that there had been "deliberate, systematic and persistent searching of a website that was clearly not intended to be public".
Robertson has denied he ever accused National of being behind a hack and said he had simply repeated information given to him by Treasury.
New Zealand's public sector watchdog has launched an investigation into Treasury's security.
