When the lockdown was announced there was a dramatic increase in the demand for flour.

When the four week lockdown was announced consumers dashed to supermarket to buy supplies, with flour quickly disappearing from the shelves.

Since then it appears to be difficult to find, but not for the reason you might think.

It turns out the issue isn't with the production of the flour - it's with the packaging.

KEVIN STENT/STUFF It continues to be a product that is hard to source but industry says there is plenty of flour in the country, just not enough packaging.

Under normal circumstances, retail flour accounts for less than 10 per cent of the flour in New Zealand, NZ Flour Mills Association executive director Niki Urwin said.

About 225 thousand tonnes of flour is produced in New Zealand each year but most of it is distributed in bulk form in tanker trucks or rail and sent to bakeries, where it's made into bread.

Smaller bakeries and cafes received their flour in 20kg bags and the last bracket of flour produced was retail flour, which came in much smaller sizes and ends up on supermarket shelves.

When the move to alert level four was imposed retail sales spiked, which put pressure on the packing lines, Urwin said.

"When the demand rose flour mills ramped up and went as fast as they could, but then ran into packaging problems and that all flowed down."

Getting packaging normally took anywhere from six to nine weeks so the issue was not producing the flour, it was how to get the flour produced into small packages and into the supermarkets.

"The retail market typically doesn't have big demands."

He said the company his mill worked with had been great and moved their production forward with urgency.

They didn't supply small retail bags but did produce 20kg bags, which he said supermarkets were now starting to take to put in their stores to fill the gap in the market.

"Those big sizes everyone is hoping will saturate the market a lot quicker."

In terms of the industry he said they had not seen this much shift in demand in at least the past 10 years.

When the lockdown was lifted and life shifted back to normal, Urwin said it would be interesting to see if the way people consumed food changed because of this.

Quick message to all those making bread at the moment. Keep the water you’ve cooked potatoes or pasta in. It will help the bread’s texture and rise. — Nigella Lawson (@Nigella_Lawson) March 26, 2020

Baking products in general had been snapped up by consumers as they prepared for the lockdown, Foodstuffs head of corporate affairs Antoinette Laird said.

This could be because people had time to create their best and brightest baking sensations.

"Our suggestion is customers focus on working through the baking items they have in their cupboards and give the supply chain a bit of a chance to get back up to normal levels."

A temporary mechanical breakdown at the Mauri Wellington Mill had halted production but general manager Steve Pedersen said the issue had been fixed and production was up and running.

He said their people were working extremely hard to restock supermarket shelves across New Zealand.

"We realise the importance of baking in the current environment and will continue to do our upmost to ensure ongoing supply to New Zealand's retailers."

Farmers Mill flour mill in Timaru had used about four years worth of their smaller 5kg flour bag packaging in just a few weeks, business development manager Rebecca Biggs said.

Their mill didn't sell a large amount of retail flour with most of their flour supply going to in-store bakeries.

This supply was not disrupted as they received 20kg bags, but demand had increased for those bags as well.

She was aware of a few stores that had put the 20kg bags out on the floor so customers had the option of purchasing them.

Their packaging was made at a plant in Auckland and the earliest they could get more 5kg bags was six weeks away.