South Australian shops will soon be allowed to trade 24 hours a day as part of new emergency measures introduced by the State Government.

Key points: Adelaide retail shops will be allowed to trade 24 hours a day as part of a 30-day trial

Adelaide retail shops will be allowed to trade 24 hours a day as part of a 30-day trial SA Independent Retailers claim they were not consulted before this decision was made

SA Independent Retailers claim they were not consulted before this decision was made Premier Steven Marshall hopes the new measures will help ease shopping pressures and panic buying

The 30-day trial comes into effect from Saturday and applies to weekdays.

There will also be extended trading on weekends, with shops allowed to open 12:00am to 9:00pm on Saturdays and 9:00am till 9:00pm on Sundays.

Premier Steven Marshall said he wanted to ease shopping pressures caused by coronavirus and to support local jobs.

"We do emphasise this is not a compulsory measure so individual supermarkets and retail outlets can make up their own mind as to when they are best served to open to support their customer base," he said.

Supermarkets across the country have been hit by outbreaks of panic buying which have seen many shelves cleared of items like toilet paper, hand sanitiser, and tinned goods.

Mr Marshall said the changes would give shops more flexibility which would help both shoppers and retailers.

"We've seen quite a lot of unacceptable behaviour from the public and this has absolutely got to stop," Mr Marshall said.

"So we've taken action to try to spread the envelope of hours that shops can choose to open."

Treasurer Rob Lucas is using his special ministerial powers to introduce the changes — the same ones he previously used to grant special exemptions to allow Boxing Day trading.

The extended hours is on trial for 30 days. ( ABC Rural: Kim Honan )

However, the changes have surprised some retailers who have actually decided to close earlier than normal to allow them time to restock their depleted shelves.

Retailers 'under duress' by extended hours

SA Independent Retailers chief executive Colin Shearing said his members were not consulted and feel "ambushed".

"It's definitely not going to work and this is putting already stressed and fragile retailers under more duress," he said.

"With this COVID-19 out there, we're going to need more time to clean and sanitise and really put additional procedures [in place] to sanitise and clean and we have to have the stores shut when we do this," Mr Shearing said.

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Mr Lucas has been pushing for deregulated hours for many years, but has been unable to get the legislation passed through Parliament.

The union representing shop workers, the SDA, has accused the Government of using the pandemic to score a political point over trading hours.

"I'm not aware of a retailer that has requested these trading hours," secretary Josh Peak said.

"In actual fact retailers are going in the opposite direction.

"I can't think of a reason the Government has done this, unless it is to score a political point, as this is just not what is needed."

Government rejects 'politics at play'

Mr Marshall said the Government consulted people across the board and has rejected suggestions it is a political move.

"This is not ideological, it is not political, it is just practical," he said.

SA Road Transport Association says trucks delivering products were struggling to keep up with demand. ( Supplied )

The South Australian Road Transport Association's Steve Shearer said store shelves were empty because trucks delivering products were struggling to keep up with the huge surge in demand.

"We are delivering massive amounts of products to the distribution centres, but they are proving incapable of handling that extra volume that they are ordering," Mr Shearer said.

"They can't receive it fast enough and they are not getting it out fast enough."

He said one of the biggest constraints to getting stores restocked was local councils restricting truck access at certain times of the day.

"Those are the things that if Government actually spoke to the people involved, they would learn and understand what is causing the shortages on the shelves," he said.

"They need to talk with us and they are not."

Charities call out for more 'younger' volunteers

Meanwhile, Meals on Wheels SA chief executive officer Sharon Broer has put out a call for younger people to join its volunteer ranks so it can keep delivering meals to vulnerable people.

"We're not short of food, our challenge at the moment is people to help in the kitchens and particularly with deliveries," Ms Broer said.

Meals on Wheels are not short on food or supplies, they need more drivers. ( ABC News: Nance Haxton )

The organisation said it was facing a double whammy — an older age group needing meals delivered and a majority of volunteers who are aged over 70.

"Younger people seem not to have the severity of illness from COVID-19 that older people do," she said.

"Older people are already core volunteers and we've almost exhausted the community of older South Australians to help and we'd really love the younger people to step up."

Foodbank has flagged suspending some of its services as it said it was in a similar position with older volunteers.

"Some of the older volunteers who feel that they are at risk with the coronavirus have elected to stay at home and some of our outlets may have to close," chief executive Greg Patterson said.

"If we can't get volunteers we will need to employ people to do these roles and that's the only other way we can do it."

Mr Patterson is meeting with the Government later today to try to secure extra funding and is asking anyone with free time to consider volunteering.

"We're the last line of defence for food relief in South Australia, if we don't operate there is no food relief," he said.

"We already supply 70 per cent of all the food to all the charities across the state.

"We've got plenty of food, we've got donations of toilet paper and everything."