ACTING Police Minister Bernard Finnigan has resigned from Cabinet and will not be replaced.

Premier Mike Rann announced this morning that he had accepted Mr Finnigan's resignation from Cabinet and Executive Council.

His portfolio of Industrial Relations will be allocated to Transport Minister Patrick Conlon while his Gambling portfolio will go to Regional Development Minister Gail Gago.

"The Premier does not intend to fill the vacancy created by the resignation," a statement from the Premier's office said.

The resignation comes after a disastrous Advertiser poll published on Tuesday which showed support for Labor had slumped to its lowest level since the disastrous State Bank election of 1993.

Opposition Leader Isobel Redmond said Mr Finnigan's resignation raised questions about who would lead the State Government in the Upper House.

Mr Finnigan was one of only two ministers in the Upper House and Labor MPs will need to vote to replace him as leader of the Legislative Council.

The position is the third-highest ranking in the Government and Caucus is not expected to meet again until May 2.

Aside from Mr Finnigan, Consumer Affairs Minister Gail Gago is now the most senior Labor MP in the Upper House.

There has been speculation today the Government will bring back former mining minister Paul Holloway, a member of Mr Finnigan's Right faction, from the backbench to fill the role.

Ms Redmond said the Government needed to explain what would be done in the wake of Mr Finnigan's resignation, which comes after only 72 days in Cabinet.

"There are some questions, I think, that still need to be answered about that resignation," she said today.

"There still are questions about whether Bernie Finnigan remains the leader in the Legislative Council and whether it is intended that he will continue to hold that office."

Ms Redmond said she expected to face Education Minister Jay Weatherill as Labor leader at the next election and the Government was doing a "spectacular job" of imploding.

"What this demonstrates more than anything is that this is a government that is far more focussed on its own dilemmas and its own disarray rather than governing for the benefit of the people of this state," she said.

"I think that there is a lack of trust.

"I think it is the dying days of the Rann Labor Government."

Mr Finnigan was the Government Leader in the Upper House and was appointed to the ministry in the reshuffle in February.

He was elected to the Upper House in May, 2006, after serving for five years as assistant secretary of the SA branch of the Shop Distributive and Allied Employees' Association.

Born in Mt Gambier in 1972, Mr Finnigan grew up on the family dairy farm at Eight Mile Creek in the South East.

He was educated at Allendale East Area School, Tenison College and Adelaide University.

He joined the ALP in 1992.

Originally published as Finnigan resigns from Cabinet