Papua New Guinea police say they will mobilise 1500 officers today and react to any unlawful behaviour.
This comes as prime minister Peter O'Neill's quest to avoid a police arrest warrant heads back to court.
Mr O'Neill is fighting a claim that was involved in allegedly illegal payments to Paraka Lawyers.
Our correspondent, Todagia Kelola, says police, bolstered by manpower for the Melanesian Arts Festival, will not allow protest action to disrupt the city or provoke unrest.
"Because there is no notice for a protest gathering police will strictly ensure there is no such gathering where some people may incite the public to create unnecessary disturbances."
Todagia Kelola says there is an expectation the arrest warrant may be set aside.