The Police Minister says the gun buyback scheme isn't as simple as writing out a cheque.

The Government's promised to compensate gun owners who hand in their semi-automatic military weapons, after they were outlawed following the March 15 attacks.

Stuart Nash told Mike Hosking the release of the details of the scheme is imminent, but won't say exactly when that will be.

He says it's a complicated and complex process.

Nash is adamant the Government must retain the trust and confidence of the firearms community.