The Police will give academic Jarrod Gilbert the data he's requested for a research project.

He had been refused the information initially, supposedly because he has gang connections.

Dr Gilbert wrote an award-winning book on gangs in New Zealand.

He went public last week with his struggles on getting information - sparking outrage over censorship.

Police then announced they'd reviewed their policies ... and now say they accept they made a mistake in not fully taking into account the nature of Dr Gilbert's research proposal.

They've apologised and granted him access to data.