Australia Day celebrations and citizenship ceremonies won't be changing dates in South Australia if the opposition wins the March state election.
A number of councils across SA are considering a shift away from January 26 formalities but Liberal leader Steven Marshall says he will block it if he becomes premier.
"Attempts to hijack Australia Day for political purposes are divisive, opportunistic and have very little support in the wider community," he told News Corp Australia on Tuesday.
But Premier Jay Weatherill said the policy announcement was an unsubstantiated ploy to get a "populist cheer".
He said no council in SA was seriously considering changing the date and questioned why Mr Marshall would take the stance.
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"They're talking about it to cover up the fact they don't have any serious policies on any of the key issues facing South Australians," Mr Weatherill told reporters.
"They don't have an energy policy, they don't have a health policy, they don't have a jobs policy."
The ban on changing the date was supported by the Australian Conservatives' state representative but was described as "jingoistic dog-whistling in jackboots" by the SA Greens.
"I thought Australia was a nation that embraced diversity and dissent not mandated conformity," Greens' upper house MP Tammy Franks said in a statement on Tuesday.
She said local communities should be able to reflect the needs and desires of their people.
"The idea of forcing a phoney national observance across the councils of an entire state, willing or not, is an extreme over-reaction to some quite reasonable debate," Ms Franks said.
