Winston Peters says KiwiRail need to tell the truth about the grounding of the Aratere ferry.

New Zealand First took to social media on earlier this week to raise questions about whether the grounding was caused by an auto-pilot mishap after a crew member went to get a coffee. 

Now, leaked documents confirm crews pressed a wrong button, sending the ship into auto-pilot and off course. 

Acting Prime Minister Winston Peters told Andrew Dickens the public shouldn't have to wait for an investigation to know what happened. 

He's questioning why it was on autopilot in the first place, and says taxpayers deserve answers. 

LISTEN ABOVE 

• Interislander ferry crew mistakenly pressed autopilot before running aground, leaked doc reveals
• 'Crikey, that’s not a denial': Peters to find out more about Aratere grounding
• 'Unhelpful': Maritime Union lawyer blasts Peters' speculation about Aratere grounding