Maritime engineers are to be brought in to examine and help develop plans for a huge expansion of Avonmouth Docks in Bristol.
A £500m overhaul was approved by the government in March.
The terminal will enable Avonmouth to take some of the world's biggest container ships.
Bristol Port Company wanted the extra facility because large vessels could not pass through the narrow lock entrances at the existing docks.
The firm said Costain and BAM Nuttall would come in to help "update existing records" during a detailed site investigation.
This would help improve final plans for the new terminal which will partially be built on land reclaimed from the River Severn.
The Bristol Port Company has estimated more than 1,200 jobs could be created as a result of the development.