General Motors is to axe production of the Pontiac Vibe - a variant of the North America-only Toyota Matrix - by the end of August.

The vehicle is built at the New United Motor Manufacturing Incorporated (NUMMI) factory jointly operated by GM and Toyota in Fremont, California and there is no word yet of a replacement GM model for the plant.

"While no replacement for Vibe production has been determined, GM and Toyota remain in active discussions regarding potential future production at NUMMI," GM said in a statement.

Though it shares most drivetrain and interior parts (the bodyshell is slightly different), Toyota's Matrix is built in Canada. NUMMI also currently builds some Corollas and Tacomas for Toyota.

According to Dow Jones, Vibe sales were down 35% to the end of May, less than GM's overall 42% decline.

GM plans to phase out the Pontiac brand by the end of 2010 and just-auto understands it has already canned any firther production - in Australia - of the G8 sports sedan, a variant of local GM unit Holden's Commodore.

Pontiac launched the Vibe at the 2000 Detroit show and sales began in the 2002 model year.

About 460,000 Vibes were produced between 2002 and the end of May this year, according to Kyodo News.

US reports have suggested NUMMI may not have a future if GM pulls out of manufacturing there.

The plant, with about 4,700 employees, was established in 1984 and "helped change the automobile industry in the United States by introducing the Toyota Production System and a teamwork-based working environment", according to Toyota.