The Commerce Commission has an open investigation into retailer Noel Leeming after receiving nearly 60 complaints about undelivered goods.
A total of 57 complaints had been lodged with the watchdog in the past six months after Noel Leeming failed to deliver purchased goods.
A spokeswoman for the Commission told the Herald it had subsequently decided to launch an investigation into Noel Leeming.
"All retailers currently offering goods online should ensure they are able to deliver them within a reasonable time or within the stipulated timeframe," she said.
"Goods should not be offered for sale when the seller, not having the goods in stock, does not have knowledge of when the item will be in stock and able to be delivered."
Noel Leeming's general manager of merchandise Jason Bell says the company is working closely alongside the Commission during their process.
Bell told the Herald the retail chain experienced an "unprecedented" amount of demand from customers during the Covid-19 alert levels which meant some orders took longer than normal.
"During this time, we were actively working with our suppliers to provide goods for hundreds of thousands of orders and made it a priority to actively communicate with customers regarding any delays in delivery," Bell said.
Elsewhere, around 100 complaints about price gouging over the lockdown were sent to the commission for investigation. Not all complaints are being followed up, however.
Kiwis took offence to the prices of supermarket staples primarily, products like butter, milk, eggs, flour, fresh produce, meats and bread.
The Commission is an independent Crown entity that is New Zealand's competition, consumer and regulatory agency.
It is responsible for enforcing laws relating to fair trading, competition, and consumer credit contracts in New Zealand.
It also has regulatory responsibilities in the nation's electricity lines, gas pipelines, telecommunications, dairy and airport sectors.
Noel Leeming is a brand owned by The Warehouse Group, who also owns The Warehouse, Warehouse Stationery and Torpedo7.