No clear cause has been found for the deaths of 16 horses which returned to Victoria by ship from a Tasmanian polo tournament more than a month ago.
The horses were found dead in Melbourne after being transported on the Spirit of Tasmania in late January.
Tasmania's Department of Primary Industries, Parks Water and Environment said on Wednesday there had been no clear cause of death and the investigation continues.
"Pathology reports have been obtained by the department and are one part of the overall investigation," a department spokesman said.
"While it is apparent this was an isolated incident, no information received to date points to a clear cause of mortality."
Further laboratory results, expected "soon" may help determine the cause of death.
There is no ongoing risk to other horses being transported across the Bass Strait, the spokesman added.
The department will publicly release the final results of its investigation, if deemed appropriate.
Australian Associated Press