Further investigations are needed at a beach where radioactive particles were found before anyone should take full responsibility, Defence Minister Andrew Robathan has said.
The Tory MP visited Fife to hand over a draft plan for further action to the Scottish Environment Protection Agency and to see the contaminated area for himself.
It comes after "significant" sources of radiation were discovered at Dalgety Bay on the Firth of Forth coast.
The contamination is thought to stem from residue of radium-coated instrument panels used on military aircraft which were incinerated and land-filled in the area at the end of the Second World War. The area faces the threat of being designated Radioactive Contaminated Land for public protection.
During a short visit to nearby Rosyth, Mr Robathan said the Ministry of Defence does not deny liability and questioned whether a clear-up of the site is needed.
"There was of course a Royal Naval air station here. It closed 53 years ago," he added. "Who knows who's liable. We're not denying liability but I think we need to be quite clear how this contamination has come about.
"For instance, there has been industrial sites. I understand there has been a ship-breaking yard just down the way. There's been earth movement which of course has of course disturbed a great deal of stuff. There's been housing estates built.
"We don't say that we are not in any way willing to help. We are willing to help. But I don't think you would expect us to accept liability before we know exactly what the situation is.
"We are therefore looking at this and we are willing to co-operate with the environment protection agency and others to find exactly what the situation is and then we can determine who is responsible for clearing it up, if there is a need to clear it up."
Last week former prime minister Gordon Brown, MP for Kirkcaldy and Cowdenbeath, called for urgent action to clean up the site. He has previously urged the MoD to "accept responsibility".