Deputy Labor leader Tanya Plibersek has denied Labor is divided on asylum seeker policy as the Prime Minister launched his strongest attack to date.

Malcolm Turnbull said more than two dozen of the Opposition's candidates were now at odds with their party's border protection policies, but Ms Plibersek said the team was "united".

Opposition Leader Bill Shorten also accused Mr Turnbull of "telling lies" over Labor's immigration stance.

Look back on the day's political developments.