Departing MP makes life tough for SA Labor

Labor's bid to retain government at the next South Australian election has become a little bit harder with a long-serving MP quitting the party.

Frances Bedford has resigned from the ALP after criticising the decision to deny her preselection for her safe seat of Florey,

Health Minister Jack Snelling will instead stand in Florey after shifting from his own seat of Playford following a redistribution of electoral boundaries.

The redistribution, which Labor challenged in the Supreme Court, appears to give the opposition a better chance of winning office at the next poll in March 2018.

Ms Bedford's decision also reduces Labor to 23 seats in state parliament's 47-seat lower house.

However, the government should easily maintain a majority on the floor of the house thanks to the continued support of independents Martin Hamilton-Smith and Geoff Brock, who both serve as ministers.

Premier Jay Weatherill has urged Ms Bedford, who has held Florey since 1997, to reconsider her decision.

She has been a popular local member and if she stands as an independent could make life difficult for Mr Snelling.