The following case was investigated by ufologist Bill Chalker. This is the only information I could find. Though it is fairly short in length, it is well-documented. This case and the 'Cressy Cigar' incident (which I may post about in the near future) are probably the two best known UFO reports from Tasmania:
In February 1976 in Kettering, Tasmania, a 39 year-old man was woken up by his young child crying. He then noticed what appeared to be a plane coming down from the eastern sky on the shore of Little Oyster Cove. A widespread glow emanated from the area. Thinking it could have been a plane accident, the man hurried towards the light, still in a dressing gown. From a small rise he had an unobstructed view, some 25 metres down the slope, of an extraordinary dome-shaped object. Windows around the object gave off a bright light The exterior looked like aluminium, with ribbing or ridging from the top. Below the windows, a small ledge led into a base, with a short vertical side. Through the three or four windows, the witness saw a tall cylindrical object (which he likened to a ship's compass mounting) and 'motionless grey shapes' (like car seats with headrests seen from the rear), perhaps entities.
A humming noise, like an electric motor turning over, could be heard as he drew closer. Then the object rose from the ground, with the noise increasing as it went. It gained elevation slowly, then increased speed. The object became a dot in the sky and was gone. The whole incident lasted about seven minutes.
The witness went back to the spot in the morning and found that the rough grass appeared to be scorched in a circle where the object had rested. This grass later died and was subsequently replaced by a 'tougher cutting grass'. When the Tasmanian UFO Investigation Centre visited the site, the affected area stood out as much greener than the surrounding area. Investigations revealed no significant differences in the thermo-luminescent content of the soil and mineral particles taken from within the affected area and from outside. The results indicated no large doses of ionising radiation. The thermo-luminescence technique allowed the analyst, Dr. G. Stevens, to conclude:
1) The death of the grasses was not caused by substantial heating of the soil. The soil on the surface had not been heated above about 170 degrees C and soil about 5 cm down had not been heated above about 155 degrees C.
2) The death of the grass and subsequent stimulated re-growth was not caused by large doses of ionising radiation. - Bill Chalker (1996)
Keep Out!: Top Secret Places Governments Don't Want You to Know About
The Field Guide To UFOs: A Classification Of Various Unidentified Aerial Phenomena Based On Eyewitness Accounts (Field Guides to the Unknown)
The Big Book of UFOs (Ufos Extraterrestrial Beings)