MPs heard a government-to-government sale is being explored by the Royal Navy for HMS Albion and HMS Bulwark, which were designed to allow Royal Marines to launch amphibious raids.
The two assault ships were already effectively mothballed at a cost of £9 million a year when the Government announced last November that they would be decommissioned.
Reports have suggested the Government could sell the two ships to Brazil for £20 million.
But defence minister Maria Eagle said she did not recognise “any of the figures that have been bandied around in the newspapers”.
Speaking at defence questions, Labour frontbencher Ms Eagle told the Commons: “Neither Albion or Bulwark were due to go to sea ahead of their out-of-service dates in 2033 and 2034.
“The Royal Navy is exploring options to sell both HMS Albion and HMS Bulwark in a government-to-government sale.
“Several potential customers have shown interest, but no final decisions have been made.”
Conservative MP Rebecca Smith raised concerns about the sale on her South West Devon constituency.
She said: “Given the fact that these ships, HMS Albion and HMS Bulwark, are reportedly being sold to another navy for a figure that could well undervalue previous spends on refits and maintenance, how does the minister justify the economic impact of their sale on Plymouth and Devonport dockyard, let alone the reduction in amphibious capability in the navy, when the promised multi-role support ships are at least half a decade away from service?”
Ms Eagle replied: “I don’t recognise any of the figures that have been bandied around in the newspapers and so it would not be accurate to take them as anything other than speculation.
“The disposal shows that we are delivering for defence by divesting old capabilities to make way for the future, as the First Sea Lord Admiral Sir Ben Key put it.
“Effectively those ships were mothballed by the previous government, so I’m not going to take any lessons from that side of the House about how to deal with these matters.”