The beta, which introduces tabbed browsing, touchscreen operations and password management to the popular browser, was announced on Wednesday.
"The purpose of doing a beta is testing," the Opera Mini team said in a blog post on Wednesday. "Opera Mini 5 has been in development for a long time and we feel it's about time to push the product live and let you take it for a spin. We rely heavily on your feedback to polish it for the final release."
Opera Mini is the most lightweight of the company's browsers, and is available as a free download. Opera Mobile is a more full-featured version that is available as a paid-for browser, but is often sold by the company to handset manufacturers for pre-installation.