Anas Sarwar has called on the SNP to act to avoid a “summer of discontent” after council workers voted to reject a 2% pay offer.
Unison members have voted by 88% against the Cosla deal and by 74% to back taking industrial action up to and including strikes.
The Scottish Labour leader said the 2% deal failed to recognise the rising cost of living.
Mr Sarwar said: “The SNP’s chronic underfunding of local government has put our vital services at risk and stalls our communities’ recovery.
“The SNP cuts to council budgets have been more brutal than even the Tories at Westminster.
“The result is strained essential services and a failure to value the frontline public sector workforce, who stepped up across Scotland throughout the pandemic.
“These workers have gone above and beyond on the frontlines of this crisis – their pay offer should reflect that.
“All Nicola Sturgeon seems to be offering them is a thank-you clap.
“But a failure of the SNP to act to support local authorities to improve this deal risks a summer of discontent.
“There is a different way. Rather than impoverishing local government, Scottish Labour would empower it.”
Cuts to councils’ non-ringfenced budgets have seen a loss of almost £1 billion from local services since 2014.
SNP finance secretary Kate Forbes said: “The SNP have protected councils from the kind of draconian cuts implemented by the Tories in a decade of Westminster austerity, which the Labour Party did nothing to stop.
“While the Tory government is imposing a public sector pay freeze and planning another round of massive austerity cuts, the SNP is introducing a pay rise for public sector workers and we are funding public services at record levels.
“At this election, the only way to keep Scotland’s public services safe is to cast both votes for the SNP to re-elect Nicola Sturgeon as First Minister and put Scotland’s future in Scotland’s hands.”