Australian politicians are being urged not to limit their public appearances following the murder of a British MP.
But the prime minister is concerned at the prospect of violence escalating during political demonstrations.
It comes after federal police thwarted an activist from ambushing a cabinet minister allegedly with a bucket of bleach.
Resources Minister Josh Frydenberg was being introduced at a climate forum in Melbourne on Thursday night when a man attempted to jump on stage, warning he'd like to hand over the chemicals to the minister.
The Australian Federal Police confirmed its officers stopped the man and questioned him later, but no charges were laid.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
"The AFP considers this matter finalised," a spokesman said in a statement to AAP.
Prime Minister Malcolm Turnbull said police paid close regard to the security of politicians.
But he warned that violence could quickly escalate from just shoving, pushing and throwing during demonstrations.
"It can very easily lead to worse and worse violence until you see people being killed," he told Melbourne's 3AW radio on Friday.
The prime minister condemned the killing of British Labour MP Jo Cox who died after being shot and stabbed in the street outside her constituency advice surgery.
He stressed that Australia had experienced very few incidents of political violence but the incident was a reminder of how strong and forceful debates should be resolved at the ballot box.
"This is a very disturbing incident."
Opposition Leader Bill Shorten described it as a shocking hate crime but urged MPs not to let "a tiny proportion of idiots" discourage them from their job.
"I have no doubt Australian MPs will continue out amongst the people - it is the single best part of the job."
Cabinet minister Christopher Pyne said the murder highlighted the vulnerable position MPs often found themselves in, but urged them not hide in their shells or stop meeting constituents.
"It is important ... that we don't change the way we behave," he said.
