Mozilla plans to release a Beta 1 version of its open source Firefox 2.0 browser on Wednesday.

The company has released several 'beta release candidates' in recent days ahead of the official beta version. The 'candidates' allow for last minute testing before the official beta code is distributed.

The candidates and the forthcoming Beta 1 are not intended for regular end users because they are likely to contain bugs.

Firefox 2.0 introduces an anti-phishing filter that automatically checks web addresses against a blacklist of known phishing sites, and a spell checker for blog comments and online forms.

Firefox 2.0 is codenamed 'Bon Echo'. The Beta 1 release was originally scheduled for release last month, and the final product is due to arrive in August.