Prison officers are calling for the installation of more mobile phone blocking equipment in jails.
The POA wants urgent government action on mobile phones in jails
Ministry of Justice figures show up to 3,500 phones were smuggled into England and Wales jails in the last year.
Prison Officers Association (POA) head Brian Caton said inmates ran criminal activities using the phones, and they could arrange attacks on prison staff.
The Prison Service says it is "vigorously tackling" the problem of smuggled mobile phones.
Mr Caton told BBC Radio 4: "Many prisoners, we know, run criminal activities, serious criminal activities, from inside prisons by the use of mobile phones.
"I'm very, very afraid that eventually it's going to get beyond that point and prisoners are going to be able to arrange for prison officers and prison staff to be attacked through using mobile phones from inside the cells."
The POA general secretary said that "with the exception probably of firearms, explosives and probably drugs, it's probably the worst thing that can happen in a prison is to have mobile phones on sale to prisoners or prisoners having them".
The association says many mobile phones are being thrown over prison walls.
In a written Parliamentary answer last week, the Ministry of Justice revealed that up to 400 mobile phones had been seized each month since October 2006.