The snap lockdown caught some businesses off guard and has prompted fears of a death knell for long-suffering shops.
Revenue will plummet 90 per cent for downtown Auckland's retail, hospitality, tourism and events sectors, Heart of the City chief executive Viv Beck said.
Virtually all businesses other than supermarkets, pharmacies and dairies were shut today, Beck said.
She said the speed of the lockdown meant many businesses had to discard stock such as food and flowers.
The lockdown brought an abrupt end to Auckland's Restaurant Month, and to Burger Wellington in the capital.
There had been some discussions about food recovery but various health and safety considerations complicated efforts to donate food, Beck said.
It wasn't immediately clear how companies forced to discard stock might be insured or reimbursed, if at all.
"We've tried to help a number of times where people have had unforeseen events, and it's very difficult."
She said construction work was off, adding another hit to the city economy.
Beck said business owners knew the delta strain of Covid was a serious threat but some were confused about how to get help for the financial impact of lockdown.
"People understand what's going on with this variant in other places. One of the things on my mind at the moment is, they've come out this morning wondering what support is available."
Finance Minister Grant Robertson said the Covid-19 wage subsidy scheme was available for businesses affected by the lockdown.
The scheme was available nationally for seven days and helped eligible companies pay staff and protect jobs, Robertson said on Tuesday night.
Roberston's office also said the Resurgence Support Payment was available for firms or organisations with one-off costs because of an alert level increase to level 2 or higher.
Work and Income's website this afternoon said applications for the wage subsidy will be open from 9am on Friday, for two weeks.
Beck said it was especially tough for businesses facing pre-lockdown challenges from City Rail Link (CRL) work and the closure of the Victoria St West-Albert St intersection.
Antony Ariano closed Da Vinci's Italian Restaurant last month, citing disruption from CRL work for ruining trade at his 10-year-old business.
Even before lockdown, some local hospitality outlets in recent weeks warned business could not be sustainable where the CRL work imposed a heavy financial and mental toll.
Beck said there was much anxiety for many of these local companies now, and some business owners would need great resilience to get through.
Beck said the strictest lockdown level fostered unique uncertainty for some businesses, partly as level 3 - which could likely succeed the current alert level - was still restrictive.
"We haven't before come out of level 4 with anything much better."