He said innocent people must be able to move about freely without the threat of violence.
Detectives confirmed that two men were wounded in the clashes.
After police dispersed the fighting, a suspicious vehicle was stopped and searched and a bundle of bushknives was found.
Police said the nine male adult occupants of the vehicle had been detained and would be formerly arrested and charged.
The clashes were filmed and subsequently posted online.
Port Moresby city manager Ravu Frank described the footage circulating on social media as disturbing and inhuman.
He called on all parties to resort to lawful means to address their grievances.
Frank assured city residents and businesses that the situation was under control and normality had been restored.
“The situation is being monitored to ensure the safety and security of everyone is maintained.
“All the makeshift shelters outside the stadium, Rita Flynn (hospital) and PILAG (Pacific Institute of Leadership and Governance) have been demolished because the privilege given was misused,” Frank said.
In the process of doing so, knives, clubs, and other non lethal offensive weapons were found and confiscated.
He said loitering and makeshift shelters would not be permitted around the vicinity of the counting centres.
For the Central Seats’ counting centres, he said it had been peaceful and orderly so the status quo would be maintained.
On behalf of the municipal government he apologised to business houses, other candidates and residents for the inconvenience caused.
It was just the latest in election related or tribal violence during the voting, which was into the last days of counting, with the writs expected to be returned by Friday.
The National newspaper reported further violence between warring tribes near Porgera claimed seven lives, taking the death toll there to 25 in a week.