Within 24 hours of the Rena grounding off the coast of Tauranga, officials were aware the ship was leaking oil and was making noises suggesting it was going to break up.
But it was not until October 9 - more than four days later - that a salvage plan was put in place and oil removal was started.
Dutch company Svitzer Salvage was responsible for drawing up the plan but Maritime NZ had the power to take control of the operation.
Documents from Transport Minister Steven Joyce's office - released to the Herald under the Official Information Act yesterday - indicate that Maritime NZ was preparing to do so five days after the grounding but it eventually decided not to.
It remains unclear if an intervention would have made any difference and the Green Party is asking whether Maritime NZ hesitated because of concerns over legal liability.
The Rena incident became the worst environmental maritime disaster in the country's history with about 350 tonnes of oil leaking into the ocean and washing up on beaches.
Mr Joyce, who led the Government response, has maintained that oil could not have been removed faster.
A briefing to Mr Joyce on the evening of the incident revealed salvage assessors were on their way from Australia and Singapore and removing the oil "will be the highest priority". That night, at 11.41pm, Maritime NZ director Catherine Taylor informed Mr Joyce's office oil was leaking from a crack in the ship.
It is understood Mr Joyce was concerned about the urgent need to appoint a salvor and the following day, Maritime NZ issued a notice to the ship's owner Costamare requiring the owner to appoint one immediately.
Svitzer was brought in but a draft plan was not ready until October 9, the same day the ship Awanuia pumped 11 tonnes of oil off the Rena.
Green MP Gareth Hughes said the documents raised further questions.
"My concern is that the Government was worried about liability issues and so refused to act. I've been calling for an independent Commission of Inquiry to answer these questions."
Documents also reveal that the people answering the 0800 help number needed more support.
"I rang the number and was told by the lady that they knew very little and said they had just been filtering the calls," a caller wrote. "Her exact words were, 'We're not actually in charge either and don't know who is ... someone's gonna get their arse kicked for this'."
To date the Rena is still intact and all but the dregs of the oil have been removed; 167 containers have been taken off, 86 have been lost overboard and 1115 remain on board.
The clean-up cost is estimated at $19.5 million and the estimated legal liability to the ship's owner is $12.1 million - meaning the taxpayer may be left with a bill of $7.4 million.
Correspondence from the minister's office was released only after the Herald laid a complaint with the Office of the Ombudsman.