Former Labor minister Jane Garrett's dramatic bid for an upper house seat fell apart when two members of her faction abandoned her at the last minute and switched their vote to her rival.

With votes between the two candidates deadlocked and tensions running high, party members who participated in the internal vote on Wednesday night even proposed tossing a coin to decide who would take the coveted safe seat.

A last-minute abandonment by two people from her own faction sank Jane Garrett's preselection bid. Credit:Vince Caligiuri

Instead it was put to a second ballot, in which two members of Labor's left on the Public Office Selection Committee changed their vote to Ingrid Stitt, a senior unionist.

Aware her dramatic tilt for the upper house had been rejected by her own faction, Ms Garrett withdrew from the preselection process.