Spanish food group SOS has said it is in advanced talks with US retail titan Wal-Mart regarding a deal to supply its Carbonell olive oil and own-brand olive oil to Wal-Mart stores.

"We are in very advanced talks about a major deal," a company spokesman was quoted by Reuters as saying, declining to give further details.

Earlier, Spanish newspaper Expansion reported that SOS was close to a deal worth millions of euros to supply olive oil to more than 4,000 Wal-Mart stores, Reuters said.