SOUTH Australian Premier Jay Weatherill will reshuffle his cabinet following senior minister Pat Conlon's move to the back bench.

Mr Conlon, the infrastructure and transport minister, said he told the premier late last year of his decision not to contest his seat at the next state election in 2014.

He said while he offered to serve in the ministry as long as the premier thought that was of assistance to the government, they both agreed now was the right time for him to step down.

"One of the great strengths of the Labor Party is its capacity to renew while maintaining its continuity of purpose and belief," Mr Conlon said today.

"The premier has a view, and I share it, that this is an appropriate time to enable the next stage in renewal."

Mr Weatherill said Mr Conlon in his role as infrastructure and transport minister had rebuilt South Australia.

"The road network and public transport networks are being transformed as a result of his leadership," he said.

"Patrick's career is a great Labor story from his childhood in Belfast to minister of the crown."

Mr Conlon's departure from the ministry has heightened speculation the premier will use it as a chance to announce a major cabinet reshuffle to give the government a clean run to the next state poll in March next year.

It's also thought likely that Health Minister John Hill would also not run for his seat again and that Environment Minister Paul Caica is planning to step down from cabinet.

Some reports suggest another spot will open up in the ministry with Industrial Minister Russell Wortley likely to lose his position.

That would free up four cabinet positions though Mr Weatherill is expected to replace them with just two new ministers, reducing the size of cabinet from 15 to 13.

The premier has offered little comment on his plans.

"Patrick's announcement will necessitate a reshuffle, which I will announce in due course," he said.