Funding pressure was a topic when the IPCA appeared before a Parliamentary select committee last month.
Warren Young, group manager operations for the authority, told media that the authority had used up its cash reserves, and would now have to operate within its annual appropriation.
There had been cases that the IPCA did not investigate because it did not have the resources, Mr Young said, including complaints of police using excessive force.
"The ones we regard as critical cases and most significant we do always independently investigate," Mr Young said. "We get 2500 complaints a year...ultimately it is important that the police take responsibility for some of those matters as well. And that's why we have a practice of referring a lot of cases back to police with our active oversight."
At the time, Justice Minister Amy Adams said the IPCA was adequately funded, and was able to take on the most serious claims: "Up until now they haven't put in a request for more funding, they may this year, we will work through that if they do".
Today, Green Party justice spokesman David Clendon called for the IPCA to become an Officer of Parliament, meaning its funding would be set by a cross party committee of MPs.
"At the moment, more than 90 per cent of the cases that warrant investigation are being sent back to the Police to investigate themselves. That defeats the purpose of an independent watchdog."