An internal review has found no fault in the police response to the Edgeware Road party in Christchurch at which two schoolgirls were run down by a car and killed.
Hannah Rossiter and Jane Young, both 16, died from injuries they suffered when a car was driven intothem at the out-of-control party on May 5 last year.
Lipine Sila was found guilty of their murders on Saturday.
The report, prepared by Inspector Neil Banks and released to The Press, said he was satisfied the police had no grounds to close down the party before 10.24pm.
"I am satisfied that once the decision was made that action to close the party was required...there was no undue delay," he said in the report.
The Independent Police Complaints Authority has conducted its own investigation but has yet to complete its report.
Nearby resident Lindsay Hay, who grew increasingly concerned about the party from 8.30pm onwards, said she was disgusted with the conclusion.
"I went there about 8.30pm and Blind Freddy could see it was getting out of hand. They could have closed it down there and then with the people they had.
"They waited around for ages doing nothing."
Mr Banks said the report established the party was not out of control until about 10.25pm.
"If it was getting out of hand earlier than that, we didn't know about it," he said.
He said he had considered whether police should have had a presence after 9.30pm, given the fluid nature of the party, but he said the party was not unusual.
Police could not sit outside every noisy party on Saturday nights, he said.
