The South Australian government shut the gates from 4pm on Wednesday, with border control officers stopping travellers at check points and recording their names and other details including their South Australian address for the period of self-quarantine.

While the direction provides exemptions to those classified as an "essential traveller", there is no application process or permits issued for those that fall under that category.

Travellers entering the state are required to self-assess and determine if they meet requirements.

In the South Australian town of Penola, Midfield Meats' processing plant employs 35 people, one of whom lives in Victoria.

The plant also employs a number of south-west contractors, including Warrnambool-based company FDPI Spares & Maintenance, which services the liquid processing needs of the dairy, beverage, food and chemical industries with preventative maintenance programs.

FPDI owner Neville Wilson said there was no issue with returning to Warrnambool but there was initially some uncertainty about workers conducting cross-border transit.

He said FDPI had about 10 employees working at the Penloa plant, which was "in maintenance shut and needed to get back online in a hurry".

Mr Wilson said it was initially unclear whether staff would need to be issued with a permit to travel in and out of the state without having to undergo 14 days of isolation.

"Some said we would need to be issued a red sticker but then the discussion was all you need was a letter that said you need to transit the border," he said.

Mr Wilson said Midfield's chief operating officer Andrew Wellington wrote to the South Australian government and "handled the situation for those transitioning the border with tanker drivers, maintenance people and (processing) plant people".

"It's good for Penola because we can get works back on track as soon as possible," he said.

"We've get 10 guys over there at the minute and it means they were allowed to return to their families if they wanted to.

"It's also positive for us going forward. The machines operating over there are pretty high tech and if things do go wrong, you've got to just jump in a car and get across there in a hurry.

"Andrew has just been brilliant. All the other contractors over there working will tell you the same thing."

READ more: Exemptions for 'essential travellers' announced as South Australian border closes

South West Coast MP Roma Britnall last week called on the state government to declare dairy and meat industries essential services to avoid shutdowns in the wake of the coronavirus pandemic.

Ms Britnell said she had received several calls in relation to the border closure and confusion about what was considered "essential travel".

"I've received calls from agricultural contractors, such as pregnancy testing and insemination of animals, and from large businesses such as those working out of Alcoa (Portland Aluminium smelter) but living in South Australia," she told The Standard.

"I've also received calls from businesses that need to get product to the Port (of Portland) such as timber. I've had massive amounts of calls actually and have just had to work through each individual one."

Ms Britnell said a permit system was not in place for those wishing to cross the border.

"It's just a process where people have to keep documentation for the purpose of travel and prove they're doing things that have been deemed necessary," she said.

"It is still an evolving situation. People will have to self-isolate if they are not doing an essential service."

Ms Britnell said hygiene and social distancing was crucial.

"People will be crossing back and forth across the border, especially truck drivers who are providing really essential services," she said.

"They just need to remember the importance of washing hands and social distancing, which I'm sure they already are.

"Those important hygiene technique is how we will manage this because we've got to keep those really essential things going.

"If you're just planning on going over to the mount because you just like that place to shop, then don't."

,Mr Wilson thanked Ms Britnell for her ongoing support of the industry.

The Limestone Coast has four confirmed cases of coronavirus after three new cases were confirmed on Wednesday.

Coach services between Victoria and South Australia will resume their normal timetables from Friday March 27 after the South Australian Government updated its border restrictions to provide exemptions for coach drivers.

We have removed our paywall from our stories about the coronavirus. This is a rapidly changing situation and we want to make sure our readers are as informed as possible. If you would like to support our journalists you can subscribe here.