The five-piece re-formed for a final world tour in 2007, but rumours of a second reunion were triggered by singer Geri Halliwell earlier this week.
Halliwell suggested that she was in talks with former bandmates Brown, Victoria Beckham, Emma Bunton and Melanie Chisholm over plans for another comeback jaunt, saying: "We are gathering information about a possibility."
However, Brown has since laughed off the "silly" claims via a post on her Twitter page.
She wrote: "World cup! wow the press are soo silly. no I am not getting the girls together for the world cup!!! (sic)"