A child pornography hearing against former ABC presenter Andy Muirhead has been told Australian Federal Police checks of a computer recovered 39,000 deleted files.

At issue in the case were about 4000 images in the Apple iMac's Unison newsgroup cache, the Hobart Magistrates Court heard today.

Andy Muirhead at an earlier court appearance. Credit:Peter Mathew

Limited evidence in the case against Muirhead, 34, was heard for the first time in a preliminary hearing almost 14 months after the former host of the popular ABC TV series The Collectors was charged.

He has pleaded not guilty to using the internet for child pornography and to possessing child exploitation material.