The girl group are due to address the press at the O2 arena in south-east London at 1200BST (1100GMT). A notice announcing the event said the band would "make an official announcement to the world regarding future plans". It is rumoured the group are planning six live shows around the world with gigs in London, Tokyo and Las Vegas, to support a greatest hits album which comes out later this year.
The band's management company, 19 Entertainment, has already registered the internet domains spicegirlsofficial.com and spicegirlsofficial.net.
19 is run by Simon Fuller, who masterminded the group's global success more than a decade ago. Under his guidance, the five-piece notched up a string of hits - including Wannabe and Two Become One - while also capitalising on their fame with a stream of sponsorship deals. Emma Bunton, Mel Brown, Mel Chisholm, Victoria Adams and Geri Halliwell quickly became household names - although they were better known as Baby, Scary, Sporty, Posh and Ginger.
The band famously spent time with Prince Charles and Nelson Mandela They sold more than 55 million records around the world, and even starred in a film, Spice World. Halliwell quit in 1998 citing "differences" with her bandmates, leaving them to complete a sold-out world tour as a foursome. The group achieved their third consecutive Christmas number one later that year, and released a third album, Forever, in 2000.
Each member has since pursued solo careers with varying degrees of success, while Posh Spice has become better known as fashion icon Victoria Beckham. E-mail this to a friend The girl group are due to address the press at the O2 arena in south-east London at 1200BST (1100GMT).