Its reports aimed to help improve transport safety rather than lay blame, and it could not be used in criminal or civil proceedings.
The TAIC's final report, covering why the accident happened, is due out next year.
Maritime New Zealand director Keith Manch said the organisation had provided TAIC with information but its main focus remained the ongoing response to the disaster; the wreckage of the Rena remains on the reef, and efforts to get containers off it continue.
Issues such as compulsory shipping lanes were matters for consideration further down the track, Mr Manch said.
"Navigational devices have their place but if you're talking about shipping lanes or navigational devices, there will be a range of other things that many people say should be put in place. They all need to be looked at and thoroughly analysed.''
Transport Minister Gerry Brownlee welcomed the report, saying it established some verified facts that would enlighten ongoing investigations.
"Today's report shows good progress is being made investigating how this accident occurred,'' he said.
But he said he did not want to implement changes ahead of the full report.
"I think going through the process is the appropriate thing. These sorts of things don't happen every day, and it would appear that there are some pretty interesting reasons as to why they managed to hit that reef just way out in the middle of nowhere like that.''
Mr Brownlee said he would not look into compulsory shipping lanes because they were expensive to set up and police.
"And in the end you would expect that someone who has an asset that is the sort of value you have in those big ships, that they'll want to behave responsibly and they'll want to navigate away from hazards like the reef.''
Asked about beacons, he said a natural item did not need to be lit up when it was clear on charts.
"The fact is it's not a danger to recreational shipping. This is a one-off event and if you look at the interim report, if you see for how long they were on track to hit it, then that starts to raise some questions that people other than me need to ask and answer.''
Green Party oceans spokesman Gareth Hughes said a wider probe was needed.
"For kiwis to have confidence in our shipping regulations and our response to oil spills and maritime accidents, we actually need a thorough investigation into the whole Rena response,'' he told APNZ.
Labour's acting transport spokesman, Grant Robertson, said there needed to be a proper inquiry into the grounding and the immediate aftermath.
"What if this happens again next week or next month? We really should have got ourselves to a state by now where we had ... at least recommendations about what needs to change in our system, to be able to respond,'' he said.
Tauranga mayor Stuart Crosby said a series of poor decisions by the "totally incompetent'' Rena crew led to the ship's grounding, with significant errors of judgement made by the Rena crew.
"I just hope these people are never allowed on to a vessel again, or in charge of a vessel, because they're just totally incompetent.''
Last week Rena's captain and navigation officer pleaded guilty to altering the ship's original passage plan, GPS log book and other documents.
Papamoa Progressive Association chairman Steve Morris said it was good to finally get some facts out into the public domain.
"It's blindingly obvious there's a ship on the reef, but the question is how did it get there? It's been five months, so it's good to get some facts into the public domain.''
Rumours about what happened have been circulating around the community for months, specifically about the ship trying to make it into the harbour in time for the tides, so it was good to hear some of the facts, he said.
While it was good the captain and navigation officer had pleaded guilty, Mr Morris felt the shipping company which employed the men was also responsible.
Local business owners who took a financial hit after the Rena grounded, and the subsequent environmental fallout, welcomed today's report.
Graeme Butler, a partner in local dolphin-watching business Butler's Swim With Dolphins, said he was pleased to see the first report into the crash come out.
He had seen some amazing wildlife over the summer, but there were no people visiting the area to share it with.
"We had eight weeks without a passenger and for a small business that's massive, and we've still got the ongoing costs of fairly big vessels.''
Rus Hawkins of fishing business Fat Boy Charters said it was reassuring to know inquiries into the accident were taking place behind the scenes.
The report had highlighted crew incompetence in the leadup to the grounding, he said.
But Mr Hawkins' main concern was the exclusion zone, which limited him from taking charters to some good fishing spots.
- Additional reporting Bay of Plenty Times
