If Labor loses – or even comes close to losing – the safe seat of Werribee in Melbourne’s west on Saturday, Victorian Premier Jacinta Allan’s leadership will be at risk and the federal Opposition Leader Peter Dutton will have a path to election victory through the southern state, says former Victorian Premier Jeff Kennett.

Labor has held Werribee, which lies in a major growth corridor, since 1979 and Labor candidate John Lister heads into the byelection, triggered by the exit of longtime treasurer Tim Pallas, with a comfortable 10.9 per cent margin.