South Australian premier Jay Weatherill may be able to form majority government after swing towards Labor

This article is more than 5 years old

This article is more than 5 years old

Labor could be set to pull off a stunning upset in a byelection for the Adelaide seat of Fisher.

The death of long-serving independent MP Bob Such in October forced the byelection.

With more than half the votes counted, Liberal candidate Heidi Harris is ahead on primary votes but is trailing Labor candidate Nat Cook in the two-party preferred count.

On Sunday the ALP had a 628-vote lead, a swing of more than 9% from the Liberals.

Early results had the Liberals firmly in front, with independent Daniel Woodyatt also polling strongly. But Labor surged ahead after polling strongly at several large booths.

Antony Green, the ABC election analyst, says the results so far are “very bad” for the Liberals. “If Labor has run a half-decent pre-poll and postal campaign, then they will win Fisher,” he said. “Even if the Liberal party do end up winning Fisher, there will be huge recriminations from this result.”

If Labor wins Fisher, it will have a lower house majority for the first time since premier Jay Weatherill scraped to power at the March state election.

Labor has only held Fisher for one term – from 1985 to 1989 – since the seat was created in 1970.

State treasurer Tom Koutsantonis posted on Twitter that he had “never been prouder to be Labor”.

Federal Labor leader Bill Shorten says the Liberal party is suffering because of the federal government.

“The latest advice I have is the swing against the Liberals there is 9.3%,” he said. “There is no doubt when it comes to broken promises, South Australians are feeling very bruised from the death of the car industry through to the government breaking its promises on the Australian Submarine Corp, threatening thousands of jobs.

“There is no doubt in my mind that the Liberals, as they approach Christmas, are suffering because of Tony Abbott and the federal government.”

The byelection was sparked by the death in October of Such, who was diagnosed with a brain tumour in March.