I thought I'd post this website here. Police are generally regarded as credible witnesses, and this is an Australian Police site encouraging officers to publish reports of sightings.

Officer Witness - Are you an officer with a UFO experience? Reports to PoliceUFO.com can be made with the guarantee of anonymity for the officer.

Tip Off - Do you have information about another officer, police-related UFO information, or news. We'd love to hear from you. Just provide as much infomation as you can.

Fill out and submit the following form or make contact at report@policeUFO.com providing the following information...

There are downloadable Summary Reports for each calendar year, also various documents. Quite a good reference site with a careful, open-minded approach to it.

One thing caught my attention, though. On the Downloads page there is an article titled
PoliceUFO.com on Radio 4BC on 21 Oct 2009.
Brisbane, Radio 4BC, "The Paranormal Panel", 21 Oct 2009.

PoliceUFO.com director Richard Jones featured as special guest on Brisbane's Radio 4BC The Paranormal Panel, 21 Oct 2009, to discuss PoliceUFO.com's inception, progress, and the place of police in the UFO phenomenon.

The audiofile was received with a large section of the interview missing. The missing section was a segment regarding a call-in and discussion about the goverment's response to alleged UFO-related animal mutilations. Several months of enquiries for the full interview was fruitless and no explanation has yet been offered, raising suspicions of a coverup, possibly in relation to National Security concerns.
Radio 4BC, The Paranormal Panel, 11.7MB.