The sequel will be formally announced by publisher 2K Games "soon", a source told Eurogamer.
While few other details were provided, Borderlands 2 will be available on Xbox 360, PlayStation 3 and PC for a 2012 release.
The first mention of a possible Borderlands sequel came when 2K Games said it could become a "long-standing franchise".
Borderlands, released in late 2009, was an open-world first-person shooter set in a Mad Max-style universe.
It sold two million units within its launch period and was given four downloadable content packs.
Gearbox Studios recently completed the development of Duke Nukem Forever and is confirmed to be working on Aliens: Colonial Marines for next year.
> Read our review of Borderlands
Watch a gameplay video for Borderlands below: