Construction of the new $1.8 billion Royal Adelaide Hospital could be delayed after its builder flagged soil contamination issues.
The 800-bed hospital, touted as the single largest infrastructure project in South Australia's history, is due to open in April 2016.
But SA Planning Department executive director Judith Carr told a parliamentary committee on Monday that the Hansen Yuncken and Leighton Contractors consortium intends to claim a three-month extension.
The consortium has submitted claims for $30 million against the government for work to remove unknown soil contamination at the site.
It also wants an extension to compensate for time lost in removing the contamination.
The final call on any extension will be made by an independent certifier.