Galaxy Poll: collapse in Labor's primary vote, putting at least 18 government-held seats in jeopardy.

A private Galaxy poll - publihsed in the Herald Sun shows Premier John Brumby will cling onto power with Greens preferences.

The poll shows a collapse in Labor's primary vote, putting at least 18 government-held seats in jeopardy.

On a two-party preferred basis Labor is leading 51-49 but the poll shows the Opposition Leader has not only secured his own supporter base but is eating into Labor's support in key outer suburbs and regional centres.