The amount of rubble blocking State Highway 3 through the Manawatu Gorge is equivalent to a building the size of a rugby field and 15 storeys high.
The sheer volume of material to be shifted from the gorge means travellers between the Manawatu and Hawkes Bay regions will have to wait at least another five months before the gorge reopens.
Woodville retailers suffering financial losses because of the closure are disappointed and shocked to hear the road will not reopen until at least mid-year.
John Gooding, of Fish Spot, hoped and expected it to be open sooner than June.
"I am absolutely shocked. I was hoping it would be sooner. I realise it is not their fault and they are trying their best but I am disappointed and it is disheartening to find out things are not going to get better anytime soon,'' he said.
Mr Gooding said the lack of traffic through the town had seen his turnover fall by 30 per cent.
"I am disappointed retailers in Tauranga are receiving assistance because of the Rena disaster but there is nothing for us. Rena was a man-made event and the gorge closure is a natural event,'' he said.
Wairarapa MP John Hayes said he tried to get financial assistance for affected businesses before Christmas.
"I have done a lot of work for the Woodville retailers and I am still batting for them. I tried to get WINZ involved but many of them told me they were okay and didn't need help. Obviously, circumstances have changed again,'' he said.
New Zealand Transport Agency Palmerston North state highways manager David McGonigal said the slip was the largest in New Zealand.
"We can't find anything comparable. It is complex and the challenge comes from the size and the environment we are having to work in. We are up against mother nature, this is what she has thrown at us.''
Mr McGonigal said crews were working daily on the benching process and the work so far was an indication of how much more they had to do.
"We are going as fast as we can and while we are looking at opportunities all the time to speed things up, we can only have so many diggers working at once. It's a big job and I will be pleased when this road reopens for everyone's sake.
"The volume of work we have to get through is huge and we realise it will be at least the end of June before we can reopen the Gorge. However, this is weather dependant. Summer hasn't been kind to anyone and we cannot work up there when it is wet as everything turns to mud and the machines slide around.''
He also said there were several unknowns.
"We have no idea what state the bridges are in under the slip and we won't be able to assess the extent of the damage until the debris is completely cleared.''