The Queenstown mountain was meant to open on Saturday but its $23million base building is not finished.
NZSki shareholder Sir John Davies said with storms expected today and Monday, he could not confirm when the skifield would open.
''But I guarantee it won't be more than a week late.''
The new building could not be certified as safe because the final 12 windows had not been fitted, he said.
The windows weigh more than 100kg each and are fitted at a height of about 10m.
''We thought 10 days ago we'd be home and hosed,'' Sir John said.
''But there's been four days we haven't been able to get a window in.
''They're massive. If they take them up, they'll get blown off and someone will be killed.''
Sir John visited the site yesterday.
''It was like a blizzard up there, just diabolical .... I nearly froze to death taking my jacket off and getting into the back seat of the car.''
Remarkables season pass holders will be able to use NZSki's Coronet Peak field instead until the skifield opens.
NZSki bosses made the call to delay the opening yesterday and informed staff.
The building was 99% finished, Sir John said, although there was fit-out work to do inside, including furniture and IT systems.
''But we can get on with that; it's the windows that are stopping us getting it signed off,'' Sir John saidContractors Arrow International had been working round-the-clock on the site for more than two weeks, with as many as 120 workers at any one time, he said.
NZSki chief executive Paul Anderson said: ''There's about 40 workers who have 40-odd days without a break to get it done.
''We're hugely appreciative of what they've done to try and get the time back we've lost to those weather days.''
He said it was disappointing not to finish on time but the company wanted the building completed to a high standard.
The new building is the final piece in a $45million investment at The Remarkables, which includes a new six-seater chairlift and snow-making equipment.
Mountain Scene
