The prime minister is due to chair a meeting of the government's emergency planning committee Cobra, as calls grow for a full review of airport security.
Ministers and officials are expected to discuss tougher checks on freight, after a bomb was found on a US-bound cargo plane at East Midlands airport.
The PETN explosive in the device was not picked up by initial tests.
A former head of security at airport operator BAA said cargo checks were less exacting than those on passengers.
Calling for a fundamental review of security, Norman Shanks said: "We're looking at introducing the explosive detection systems that we currently use for passengers' baggage which goes into the hold.
"Now this really can't be introduced for every package, but it could be used for packages coming from areas where there is a known risk".
Home Secretary Theresa May has pledged to review air freight security following the terror alert on Friday.
BBC News
