"The browser is the gateway to the web, and we want to make that experience as good as possible," said Mozilla Europe president Tristan Nitot.
"No software as complex as a browser can ever be perfect, but we want to make absolutely certain we have all the major bugs ironed out before we release the new version to the public."
When the new version finally becomes available, Mozilla is hoping to set a Guinness World Record for the number of software downloads in 24 hours.
Users are invited to sign up on a dedicated Download Day 2008 website to be informed of the official release.
The latest version of Firefox boasts security features including built-in anti-malware, more intuitive search, a new download manager and customisation features.
March figures from web survey firm XitiMonitor show Firefox holding a 28.8 per cent share of the browser market, reflecting "slow but steady progress" .
This jumps to 30.1 per cent over the weekend, suggesting that a growing number of surfers are adopting Firefox at home.