Opposition to the Brighton bypass bridge over the Jordan River in southern Tasmania escalated after the April 12 decision by the Tasmanian heritage minister Brian Wightman to give final approval for works to proceed.
The bridge will destroy kutalayna, a site of 42,000 years of Aboriginal occupation.
On April 14, protesters entered the site and stopped the works. On April 15, 21 people were arrested after protesters scaled the fence and entered the site in waves, stopping the work on several occasions.
The Construction Forestry Mining Energy Union and the Australian Services Union support the call from Aboriginal activists to re-route the road. Both unions also want the state government to stop using non-unionised labour on the development.
On April 13, the Greens moved a motion in the state parliament to stop works and re route the road. Instead of supporting the motion, the Liberal party united with the Labor party to defeat it.
Protesters have said they continue to oppose the works and call on the state Labor government to respect Aboriginal heritage.