The track development was first scheduled to open in April this year, but that was extended to September. It was then moved to November.
The ceremonial opening was held on November 30, but a landslip meant the track opening was again put off, until December 20.
Conditions at the slip site were so challenging a 1.7-tonne digger went 30m over the side on December 6 when the ground gave way, and had to be retrieved by an Iroquois helicopter last week.
The person in the digger was able to get out safely before it slipped.
Doc is investigating the incident. It is also seeking further geotechnical and engineering advice to find a more suitable way to build the track in the slip area.
The new delay has affected 2642 people booked into huts.
Greymouth operations manager Shane Hall said the slip had got worse as the ground became saturated.
Contractors were unable to continue working safely in the area until the conditions improved.
As a result, Doc had extended the partial closure of the track, the middle and final section being expected to open on March 1.
"We know the extended partial track closure will be disruptive and disappointing to visitors who have booked their huts and made plans to visit the Coast, especially over the Christmas holiday period," he said.
"People who have booked on the track during these dates have been notified by email of the extended closure period on the middle section of track."
The problematic area is located on a steep face between the Moonlight Tops Hut and the Pororari Hut.
This area has a formal closure in place, which means it is illegal for any unauthorised person to enter.
Mr Hall said the West Coast had been battered by severe weather, rain and wind over the past months, and the affected area had experienced unusually high volumes of rain, leading to extremely wet ground conditions.
"In the first 10 days of December, Greymouth and Westport experienced double the average rainfall. This is on top of an unusually wet November."
The Paparoa Track will be New Zealand’s 10th great walk, and the first great walk designed for both mountain bikers and walkers.
It is being built in conjunction with the Pike 29 Memorial Track, which will take visitors to the Pike River Mine memorial site and information centre, built to commemorate the lives of the 29 miners who lost their lives in the 2010 mining disaster.
