The spreading of excrement around the inside of changing rooms at the Oval sports ground on Princes St appears to be a random act of offensive behaviour.
Alan Peat, of Purakaunui, said he had been told the Dunedin City Council-owned changing rooms had been "trashed" by rugby league players who used the grounds on Saturday, April 9.
But council sports fields and facilities officer Harold Driver said he believed the incident occurred after the league players had left the rooms.
Mr Peat said he was told faeces and broken glass were strewn around the changing rooms.
If the league players were responsible they should have to pay for cleaning it up, he said.
Mr Driver said the offenders were "definitely not league players".
"I've checked with the league reps and they said it was clean when they left," Mr Driver said.
"It appears someone got in and did this between the time when the team finished and when the facilities were locked up."
Excrement was spread around, but there was no broken glass, he said.
Cleaning the changing rooms took about two hours, but "not a great deal of cost".
South Zone Rugby League general manager Steve Martin said the team had no knowledge of the incident and had left the premises "in pristine condition".
Asked whether it could have been a deliberate attempt to discredit league players, Mr Martin said he "couldn't be drawn" on any speculation about possible motives.
"We are grateful for the opportunity as a league community to use the facilities," he said.
Senior Sergeant Mel Aitken said anyone caught would be likely to be charged with offensive behaviour.
Conviction can result in a maximum fine of $1000.
League is two weeks into its first winter competition in Dunedin after a three-year absence.
There are four teams in the competition.
