Retailers say they were banking on being able to resume online trading sooner than next week.
The Government on Monday announced that the level 4 lockdown - which allows only essential businesses to operate - would be extended until late Monday evening next week.
Initially set for "at least" four weeks, many hoped that the restrictions would lift on Wednesday night.
"There's obviously some really good health outcomes coming through in terms of what we're seeing around the virus but there is some real disappointment in the retail community that the move to level 3 has been postponed and that when we do move to level 3 stores won't be able to open even if they can do so safely," says Greg Harford, chief executive of Retail NZ.
He told Newshub the decision is a "mixed bag" for retailers, adding that many store owners believe the level 4 restrictions were too strict on businesses able to sell online.
"It's hard to see how a ban on shopping online helps to stop the virus. There's plenty of situations where people can buy online and have those orders fulfilled within a family bubble in some cases and certainly without creating a health and safety risk. We think online shopping should have been permitted some weeks ago and were really keen to see it up and running as soon as possible."
Economist Shamubeel Eaqub says the easing of the lockdown level will mean Kiwis will start to spend again, but it won't be a miracle cure.
"We should expect a rebound but we shouldn't expect that to be long-lived and we shouldn't expect it to be very big," Eaqub told Newshub.
"Under level 3 we'll still have a lot of restrictions, so people's movement will still be restricted, people will be working from home a lot more, businesses won't be operating at 100 percent. That means there are still risks to people's spending, people's jobs, people's incomes and that is likely to not just affect physical restrictions to how we work but also the sentiment and our willingness to go out and spend."
Under level 3, supermarkets, dairies and petrol stations will continue to operate as they have been over the past four weeks, with customers allowed inside.
All retail stores and malls must stay shut, but click-and-collect online shopping can begin. The key principle guiding what is allowed is that face-to-face transactions can't take place.
Real Estate agents will be allowed to resume work. They will able to enter people's homes but cannot have customers in their office, nor can they run open homes.
Construction companies will also be allowed to reopen, but strict hygiene measures must be put in place and office staff are encouraged to continue working from home.
Trades that require face-to-face contact or sustained close contact such as hairdressers, massage therapists, and personal trainers will not be allowed to open.
Dr Paula O'Kane, a senior lecturer in human resource management at the University of Otago, told Newshub that she believes the Government's decision was "very thought-out and considered".
"It's an announcement that works quite well - leaving it a few days longer gives businesses time to prepare, time to get their ducks in a row - from a hospitality and retail perspective to organise their online ordering, to organise their phone ordering and their contactless kerbside delivery," she said.
"So I think we're moving sensibly into level 3, we're going to get more people back into the workplace which I think is very positive to reduce social isolation and for wellbeing on many levels for many people. I think it's been done in a sensible way."
In announcing the decision to extend the lockdown, Prime Minister Jacinda Ardern said on Monday that the country had given too much already to end alert level 4 this week.
"The message to New Zealanders is you have sacrificed too much to lose those gains now," she told media.
"Let's lock them in and do everything we can not to go backwards, and keep moving forwards successfully."
The situation will be reassessed two weeks after the country shifts to level 3.