A pod of about 70 whales are reportedly stranded at Macquarie Harbour near Strahan.
Marine conservation experts from the Department of Primary Industries, Parks, Water and Environment are being deployed to the area to assess the issue.
The animals are believed to be on a sandbar inside Macquarie Heads.
The species is believed to be pilot whales, however the department has yet to receive confirmation of this.
DPIPWE staff and Tasmania Police are on site and managing the incident.
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"Marine experts will assess the scene and the situation and will provide updates as the day progresses," the department said in a statement.
Once marine conservation experts arrive at the scene, they will determine what resources are required.
"If it is determined there is a need for help from the general public, a request will be made through various avenues," the statement reads.