He said staff were dealing with 2800 complaints. In contrast, the Ombudsman's office told a parliamentary select committee it finished the 2011 year with 1359 complaints and the 2012 year with 1746 complaints.
Mr Donnelly said this will be a factor in an investigation into the way the act was handled across the public service. He said the inquiry would aim to discover if the delay was caused by the way public agencies responded to requests.
He said the law stated information should be released unless there was good reason to withhold it.
A recent investigation into the Ministry of Education's handling of requests to do with Christchurch schools raised questions about the processes used by government agencies to deal with requests.
Constitutional lawyer Mai Chen said the problems raised questions about how well public servants understood a law intended to give balance to the "David and Goliath" inequality between citizen and government.
"I am concerned that officials sometimes reflect their ministers. I'm concerned some of the reticence may reflect the priorities that ministers give to compliance with legislation."
She said the government expected citizens to comply with laws and it should do so with the act.
"If they don't mean to do it, they should repeal it."
Both the Green Party and Labour Party have spokeswomen for open government - with Labour's Clare Curran, saying it would become a ministerial responsibility when the party was next in office.
"There is an emerging crisis with our watchdog agencies," she said.
"It is a paralysis of democracy."