The council splashed out £16,000 on recruiting for a new role reporting directly to the chief executive.
The money was spent on the lengthy recruitment process for appointing a new head of external affairs.
The person appointed will report directly to chief executive Eleanor Kelly and will earn up to just over £93,000 a year plus benefits.
They will manage the council’s internal and external communications and external affairs, and will provide policy support to the leader and cabinet.
Councillor Anood Al-Samerai, leader of Southwark Liberal Democrats, criticised the council spend.
“At a time when we are repeatedly being told by the Labour administration that money is tight and needs to be saved in order to support frontline services, it seems ludicrous that £16,000 has been spent on the recruitment process for a spin doctor at Southwark Council,” she said.
In response, Southwark Council leader Peter John said the Liberal Democrats were “hypocritical”.
“It’s completely hypocritical for the Lib Dems to pretend to be shocked about a recruitment system that they used when they were in power in Southwark,” he said.
“They paid nearly £20,000 to try to recruit a director of regeneration and neighbourhoods – a recruitment that didn’t even work as the person appointed turned down the job.”