Six deliveries have been targeted by armed criminals in the last few weeks, according to Kevin McMahon of Siptu, who also condemned a decision by the minister for justice Michael McDowell to postpone a meeting scheduled for this Tuesday to discuss safety measures for security guards.

McDowell met with representatives of the cash delivery companies and the banks nine days ago and criticised security lapses in the companies and the banks.

"The minister is blaming the security industry but in each of the six armed attacks there was no garda armed response unit in the area to assist the security workers whose lives were under threat, " said Mahon.

Last Tuesday, in broad daylight, an armed gang fired twice at point-blank range at the windscreen of a van delivering cash to the Ilac shopping centre in Dublin city centre. "Fortunately, this time the bulletproof windscreen withstood the blast. But it is clear these gangs are now shooting to kill first, " said Mahon.

Unarmed security workers are not equipped to deal with this threat, he said. "It is up to the minister to resource the gardaí properly to confront these gangs and provide more armed escorts".

The drivers in the Ilac centre heist did not get out of the van and the raiders eventually sped off without any cash.

Van drivers foiled another armed attack the previous week in Killester in the north of the city.

"This time the armed gangs - posing as construction workers - tried to ram a Brinks Allied van with a 4x4 jeep with steel girders attached, " Mahon said. "But the driver managed to reverse the van and sped off to Santry garda station.

"Having been foiled on two occasions because they couldn't gain access to the vans, we fear that these gangs will start using explosives as has happened in Sweden recently, " warned McMahon.