Speaking at the Morrisons spring tasting, Purdie said consumers were likely to look to other countries if Australian wine prices rise too much.
He said: "If we lose the chance to have promotional activity around Australia and deals it will be South Africa or Chile that consumers look to. I think they are going to be bigger than Australia in the UK. It will be interesting to see."
Morrisons has added more wines to its The Best range, bringing the total number sold under that label to 18.
There are also additions to the supermarket's Organics range; an Argentin ian Bonarda/Sangiovese and Chardonnay, a Chilean Sauvignon Blanc and a Corbières 2002.
Purdie said: "I think organics have changed in terms of quality now. I think the danger was 18 months ago was they were not so good, but they've improved since then."