Bernardi would split SA vote: Weatherill

Any move by conservative Senator Cory Bernardi to split from the Liberals would be "catastrophic" for the party at the next South Australian election, Labor Premier Jay Weatherill says.

Mr Weatherill says such a decision would split the conservative vote in SA between One Nation, Nick Xenophon, Cory Bernardi and "any other right-wing nut job that decides to jump up in the meantime".

Senator Bernardi appears set to quit the coalition as early as Tuesday to establish his own political party.

Mr Weatherill said that would result in continued disunity and fighting on one side of politics compared to Labor's unity and competence.