Independent MP Geoff Brock has announced he will support a Labor minority government in South Australia.

Mr Brock, the MP for Frome, will take up the roles of Minister for Regional Development and the Minister for State and Government Local Relations in the new Labor government.

He says his decision, which will see Labor hold a two-seat majority, was brought on after news that fellow kingmaker Bob Such would need surgery and up to two months' leave from parliament.

"The circumstances arising from [Saturday] morning gave me the opportunity to look at it. I want stability out there," Mr Brock said.

"I could have quite easily let it go for another week and that's what we thought we would do, but Dr Such has asked for two months' sick leave from the parliament.

"I will accept an offer made to me by the Premier to be the Minister for Regional Development and the Minister for State and Government Local Relations."

He says the portfolios will allow him to "provide a voice for regional South Australia".

The Labor Party had won 23 seats in the election, while the Liberal Party had won 22.

Twenty-four seats were needed to form a minority government, meaning the Liberal Party needed the support of both Mr Brock and Dr Such.

"Given the result of the state election last week, pressure has been brought to bear on the independents to make a decision who should form the government," Premier Jay Weatherill said.

"Mr Brock has chosen the Labor minority government here in South Australia."

The Premier visited South Australian Governor Kevin Scarce on Sunday afternoon.

"We've appraised him of the agreement we've reached and we've provided the relevant documentary evidence of that agreement. It's now a matter for the Governor to consider those matters and he'll call on use in due course," Mr Weatherill said.

Brock says he will remain independent despite ministry position

Mr Brock's support will see a fourth successive Labor government in South Australia.

He says the agreement specifies his independence and freedom to vote however he chooses on certain issues.

"In the agreement I have with the minority Labor government I have expressed... [that] I have my independence as much as I can. That's very clear in there," he said.

"I will remain an independent, I will be able to vote as I see it on certain issues.

"But certainly I won't be voting against supply or to bring the government down."

Mr Brock says he tried to contact Liberal leader Steve Marshall on the phone but it went to voicemail so he left a message.

He says he had hoped to speak to Mr Marshall personally.

"If I had have gone [with] Steven it would still be 23-23. I don't see the stability in that," he said.

Mr Marshall says the people of Frome will be disappointed with their MP's decision.

"It was clear, I think, from the messages that were going to Geoff Brock that the people of Frome didn't want a Labor government," he said.

"Labor has no mandate whatsoever. They dropped their vote. They dropped three seats, lost three ministers at this election, and I don't think they have a mandate whatsoever.

"We received more than 92,000 additional votes over Labor at the first preference level, so clearly I don't think they have got a mandate. I think it will be a very interesting time."

Mr Marshall says he will not go into any potential deals that he had offered Mr Brock and Dr Such.

Mr Weatherill says in coming days his government would be revealing new policy agendas concerning regional South Australia and small business.

He has also flagged looking at how the South Australian electoral process was conducted.

The final allocation of preferences in the election was expected to be completed by Sunday afternoon.

ABC/AAP