The system for vetting PhD students from high-risk countries is not working and is likely to be taken out of universities' hands, the conference was told.
Michael Murtagh, a senior civil servant in the Foreign and Commonwealth Office, said take-up of the voluntary vetting scheme among universities varied from "patchy" to "not very impressive at all". He confirmed that the scheme was under review and was likely to be made compulsory.
Mr Murtagh, deputy head of the non-conventional weapons export policy section at the FCO, said: "There is a definite danger out there and we are seeking to try to stop it, but the failings of the system are obvious."
In theory, all postgraduate research applications from students in the 11 "countries of concern" wanting to work in a high-risk area should be referred to the Government for approval. But in practice the race to recruit foreign researchers means some universities ignore the scheme.
Mr Murtagh told delegates that 471 students were referred for checking last year. Of these 17 were refused. But it is up to universities to decide whether to follow this advice. Some do not.