Liberal Senator Simon Birmingham says he is certain former South Australian Liberal leader Martin Hamilton-Smith has no chance of retaining his Adelaide seat at the next state election.

Mr Hamilton-Smith has switched his support to the Labor Government and taken a ministry, which Senator Birmingham says is the highest act of betrayal towards voters in the Waite electorate.

The former Liberal says he is now a Liberal independent and Labor has given him the portfolios of Trade, Defence Industries and Veterans’ Affairs.

Senator Birmingham says the voters of Waite will not accept the defection.

“Waite is an electorate that consistently votes Liberal, it’s an electorate that voted very, very strongly for the Liberal Party at the last election,” he said.

“His voters will see him as a rat and I have no doubt that the voters in Waite will want the first opportunity to vote against him.

“All this is about is Martin getting to be a minister again and it’s very, very sad. There’s nothing about what Jay Weatherill and the Labor Government stand for that is consistent with Martin’s beliefs or views or anything he’s claimed that he’s wanted to achieve in politics.”

Graffiti daubed on electorate office

Someone has taken out their anger overnight at Mr Hamilton-Smith’s suburban electorate office, daubing it with graffiti.

The message across the front doors and windows in red paint reads: “Deserter. The community won’t forget. Your time will come”.

Political analyst Professor Clem Macintyre says Mr Martin Hamilton-Smith’s switch of support consolidates South Australian Labor’s grip on power.

“Barring resignations or deaths and by-elections … we wouldn’t expect the numbers to change and Jay Weatherill would be much more confident that he is securely in office for the period through to 2018,” he said.

“With Martin Hamilton-Smith I think they’ve got a very able former opposition member sitting in their Cabinet.”

SA has fixed election dates provided a government runs its four-year term.