The government has authorised the sale of 1,000 tank guns to Ukraine on condition that the weapons are not sold on to a third country.
The decision on Wednesday was in response to a request by the state-run weapons company - the Swiss Ordnance Enterprise Corporation - to supply a Ukraine firm with the guns.
Cabinet spokesman, Achille Casanova, said that before the sale could go ahead guarantees must be obtained from Ukraine that the tanks on which the weapons are to be mounted will not be exported without Switzerland's permission.
The condition has been imposed even though the guns account for only about 1.5 per cent of the total manufacturing costs of the tanks.
Casanova said the condition reflected the cabinet's view that the guns were a crucial element in the tanks' effectiveness as weapons. In this light, he said, any potential economic advantage to be gained by the contract was of little significance.
swissinfo with agencies