A lawsuit against the Edinburgh council could be much greater than the £50m reported last week in the Sunday Times.
Leading insurance companies are looking for reparation from the council, alleging it failed to build adequate flood defences to stop the Water of Leith bursting its banks two years ago.
It is understood the lawsuit could further affect builders and contractors commissioned by the council.
The lawsuit is subject to a feasibility study conducted by a consortium of chartered loss adjusters, which has consulted a leading engineer and a litigation solicitor.
A consortium representative said the £50m figure was "subject to the feasibility study," and the precise figure had not yet been collated.
But he said as personal injury issues had not yet been addressed, the figure could increase substantially.
He said: "This matter came out while under review and the Sunday Times article was premature."
He confirmed action would be taken soon.
According to visiting professor at the Benfield Greig Hazard Research Centre David Crichton, such an action was unlikely to be possible in England.
He said this was due to the absence of legislation similar to the Flood Prevention and Land Drainage (Scotland) Act.
This legislation demands local authorities publish details of what they do to reduce flooding every two years.
"This creates a statutory duty that does not apply in England," he said.
The floods in April 2000 wrecked homes in Edinburgh's Georgian New Town, including listed buildings.