Crews building the final stretch of the Midland Highway will have to check for a threatened frog before digging each day under federal conditions attached to the project.
The 10-kilometre section between Campbell Town and Conara is the final part of the $605 million Midland Highway Action Plan.
Work is due to start later this year and finish in late 2028.
Under the federal approval conditions, workers must survey each section for the green and gold frog within 24 hours before any clearing begins.
If one is found, work must stop in that area until a fauna spotter-catcher can relocate it.
The conditions also limit how much habitat can be cleared.
Crews can remove no more than 0.31 hectares of threatened native grassland and 14.1 square metres of grassland flax-lily habitat along the route.
To offset the impact on the flax-lily, the state must permanently protect a patch of land near Brighton and manage it for 20 years.
The conditions were imposed by the federal environment department, which approved the highway upgrade on July 7, 2025.
The latest approval was for a separate wildlife management plan the state had to lodge before work could begin.
The upgrade will widen the road, add sealed shoulders and overtaking lanes in both directions, improve turning points and install flexible safety barriers.
The state and federal governments are jointly funding the work.
About 143 kilometres of the highway has already been upgraded as part of plans to bring the entire road to a three-star safety rating and support the 110km/h speed limit.
A contract for the final section is expected to be awarded in the coming weeks.
