Woolworths has dumped Australia's best-known tinned tomato brand, SPC Ardmona as its private label provider after cutting a deal with a new Australian supplier for the Woolworths-brand product line.

The tomato deal has the potential to undermine SPC's $70 million supply deal with Woolworths, which was only made on a handshake and is under review by the supermarket giant.

Woolworths came to the rescue of SPC two years ago with a five-year deal to buy its private label tinned fruit from the Shepparton processor but it's understood concerns over quality, sizing and supply have emerged just two years into the agreement.

The supermarket's decision to buy its private-label tinned tomatoes from a new Australian supplier may blunt SPC's ability to mount a public campaign urging shoppers to invest in its locally grown product and locally produced lines to support its business.