Shopping entirely at the supermarket and shopping less often are two reasons Kiwis might be feeling like they are spending more on groceries during the lockdown.

It certainly is not because there are fewer specials than ever before, because that is simply not the case the nation's biggest supermarkets told the Herald.

New World stores have 5000 items on promotion in a normal week, with the price cut further by in-store promotions as well.

In the North Island last week, New World stores averaged 4997 products on promotion, Foodstuffs head of corporate affairs Antoinette Laird said.

"I can unequivocally tell you that there are not [fewer] specials which, considering the abnormal circumstances we are in, is a sterling effort," she said.

"What we are seeing nationwide, and it's certainly reflected in my household, is customers buying higher volumes of items which tend to push the basket price up."

Elsewhere, the average Countdown store had around 25,000 products on its shelves, a spokesperson told the Herald.

There were about 3400 products on their 'Great Price' programme, offering low prices for customers. Thousands of products were on promotion too, they said.

Traditionally, Countdown trends suggest customers did a number of top-up shops throughout the week.

"But at the moment we're seeing customers shop less often as they try to stay home as much as possible during the lockdown," the spokesperson said.

Due to the Covid-19 pandemic, Foodstuffs had witnessed a dramatic increase in the purchasing of cleaning and hand washing products.

The increased volume of cleaning product sales suggested people were buying more of them regularly when compared to non-lockdown times.

Meanwhile, household grocery shopping was not generally all done at the supermarket, Laird told the Herald.

Many people split their shopping between produce shops, takeaway outlets, restaurants, butchers, liquor stores, cafes and pubs.

"The reason shoppers are 'feeling' like their grocery bill is higher than normal is most likely because they are spending more at the supermarket because they don't have access to the other food channels they normally use," Laird said.

"It's not because prices have increased or specials have decreased, its simply because household spend is concentrated through one channel."