Superintendent Bob Noble of Wagga police likened the matter to "organised crime" as he appealed for anyone with information to come forward.

At a press conference, Superintendent Noble said Strike Force Seger had been established in April 2019, after a series of reports were made to police.

"This strike force was established by rural crime investigators attached to the Riverina police district in respect of allegations of the large-scale fraud involving the sale and the purchase of cattle in the Riverina," he said.

"Our investigators are examining claims that up to $2 million worth of cattle may have been fraudulently purchased and sold in a series of events that may have included cattle that didn't exist or cattle that may have been deceased prior to their purchase or sale.

"Over the last two days our rural crime investigators mustered more than 400 head of cattle at a property ... near Wagga. Those cattle were yarded and examined and a number of those cattle have been seized.

"Further examination and investigation is ongoing in respect of the rest of that mob."

Police have not laid any charges in relation to their investigations.

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Superintendent Noble urged anyone with information about this or other or any related allegations of fraud or theft involving cattle, or any other rural crime in the area, to come forward.

"We do believe this is not an isolated incident and it is going to be an investigation of some scale and it will be ongoing for some time," he said.

"What we are talking about here could be described as organised crime in relation to the rural industry and just like any organised crime, or any crime of any sort, we take it very seriously.

"We will rigorously follow up every lead in relation to this matter and if it leads us elsewhere, well so be it. We will examine every possibility."

While the police investigation has been mainly centred on the Riverina, Superintendent Noble said he "wouldn't be surprised where the tentacles of this particular operation" reached.

"Obviously we're talking about, at this stage, $2 million worth of stock - that of itself is significant - but it could turn out to be more, so, as I say, we're very serious about this," he said.

"We've gathered a large body of evidence and we continue to catalogue evidence, such as what we obtained over the last couple of days. We're far from finished.

"We can't really divulge too much about the MO at this stage, but it would be fair to say there is a fairly significant level of sophistication around this matter.

"To that end, it could be described as organised crime. We take that very seriously."