Labor has promised to campaign hard against Liberal MP Andrew Laming after he was exposed for bullying constituents on social media.
Dr Laming has been forced to apologise after harassing two prominent women from his federal electorate over several years.
The prime minister has reprimanded the Queensland backbencher over his "disgraceful" behaviour.
Scott Morrison called Dr Laming into his office after learning of the vulgar online abuse.
"I told him to apologise and deal with it," he told reporters on Friday.
Mr Morrison is expected to enforce a "zero tolerance" approach to the rogue backbencher, who has been regularly criticised for his poor behaviour.
"He is very clear about my expectations," the prime minister said.
But Opposition Leader Anthony Albanese said Dr Laming had been let off lightly for years of vile abuse.
"One again Scott Morrison has got out the feather against a Liberal MP in Andrew Laming," he told reporters.
"Quite frankly, the prime minister's response is totally inadequate, as it always is."
Mr Albanese said the distraught victims of Dr Laming's abuse had suffered years of obnoxious trolling.
"In my view, Andrew Laming isn't fit to continue as a member of parliament," he said.
"And if the Liberal Party want to continue to associate themselves with him, then I look forward to campaigning with the Labor candidate in that seat."
Australian Associated Press