Lord Drayson, who was a science minister in the last Labour government, said research was being “choked off” because airlines and ferry companies were refusing to transport the animals.
He said “extremists” had “picked off” the companies which have now pulled out of transporting laboratory mice and other animals.
Stena Line has reportedly followed DFDS Seaways and P&O Ferries in halting the carriage of test animals, closing the last sea route for medical researchers.
The Channel Tunnel is also understood to refuse the trade, while no UK-based airline, including British Airways, will carry laboratory animals.
Although imported animals only account for a small proportion of those used in British laboratories, scientists say access to genetically modified strains bred overseas is vital for some advanced research.
Lord Drayson said that unless the Government took action to restore the import of test animals, university research in the UK would “wither” and patients needing new treatments would die.
“What the extremists have done successfully over the years is identify weak links in the chain and to target the people at those weak links to be able to stop the process,” he said.
“The important thing is for the Government to work with the transport industry as a whole to get together to agreement that all transport companies, whether they are airlines or ferries, will support the transport of animals and therefore people cannot be picked off.”
He said that the pull-out of the last ferry company should be the “red flag” for all sides to come together to deal with the problems.