Eight skydivers and their Queenstown pilot, Chaminda Senadhira (33), died in the crash, which occurred about 1.15pm on September 4, 2010, shortly after the Fletcher FU24 turboprop plane took off from a private Fox Glacier airstrip.
The crash occurred on same day as Christchurch's first large earthquake.
Four of the passengers were overseas tourists intending to do a tandem jump, and the other four were skydive masters employed by Skydive New Zealand.
Company co-owner Rodney Miller (55), of Greymouth, died in the accident.
The commission's website had indicated a draft report would not be available before this month, but Mr Northcote said the deadline had been extended until early next year.
There was no new information to release about the accident since an interim factual report was put on the commission's website in October last year, Mr Northcote said.
The investigation had moved into the analysis stage, he said.
"Most of the fact gathering has been complete and a draft report will be prepared for the commission. Once that has been accepted by the commission, then there will be consultation with the parties involved. Any further evidence and submissions would be taken into account before preparing a final report," Mr Northcote said.
Last year's interim report stated it had not been prepared as a draft report for the parties to comment on but was an "interim factual report" released in the interests of transport safety.
The interim report did not contain any analysis of, or findings on, the Fox Glacier accident, but it did issue two urgent recommendations to the director of Civil Aviation regarding loading limitations for the Fletcher FU24-type of aircraft.
Airworthiness directives restricting the number of passengers in the forward cabin to six and amending flight manuals were subsequently issued on September 11, 2010.
Previously, there had been no restrictions on the number of passengers, which had typically been eight.
The changes mean pilots also have to weigh passengers and their equipment before each flight and take note passengers are positioned inside the aircraft so as not to upset the centre of gravity.
The interim report also stated the commission was pursuing at least six other lines of inquiry, including the aircraft operation, engine fitment, conversion for parachuting, aircraft loading, fitment of passenger restraints and parachuting regimes.
