Speaking to media on Friday afternoon, Jeroen Weimar didn't deny there was cause for concern in the region, which borders the already locked-down Mildura Council area, amid worries Mildura's outbreak was spreading through "family networks" along the Murray River.

"We should all be concerned, wherever we are in Victoria, where we see transmission and it feels like it's not naturally running out of steam," he said.

"There's only a limited amount of tools we've got to deal with it.

"The best tool we've got is vaccination … but where vaccination rates are (low) then there's not many other levers we've got left, apart from the selective shutdowns and lockdowns."

The Swan Hill local government area has a first-dose vaccination rate above 95 per cent, but as of Monday just 67 per cent of residents were fully immunised.

However, there are concerns the numbers might be much lower in reality due to a high number of migrant workers, especially in Robinvale.

Mr Weimar admitted international workers created "a gap in our data", but said authorities were working closely with farmers and local health teams to get everyone vaccinated, regardless of nationality.

"If you've got a Medicare card that's great; if you don't, that's not a problem either," he said.

"We'll still jab you as long as we have some way of identifying you.

"What the team has been doing is going to individual farms and doing vaccination drives there and really focusing on getting to any workers that are there.

"If necessary, we ask no questions. We just want to make sure people are vaccinated properly."

Mr Weimar said at present COVID-19 exposures in Sunraysia's agricultural industry were confined to "just one or two farms in the Robinvale area" and transmission in homes was the primary concern.

"We are getting (outbreaks) in homes, because homes are where the controls are non-existent, because people are sitting behind closed doors," he said.

"I'd say to Swan Hill and Robinvale, please do the right thing. Get tested, get vaccinated … and stick with the directions that are relevant to you locally."