A builder told today of his shock at finding a cache of World War 1 hand grenades during renovation work on a house.

Patrick Flood, 31, was digging trenches at the ruins of the property in Heytesbury Lane, Ballsbridge at around 11.30am when he unearthed six grenades.

The gardaí and an army bomb disposal unit were called to the scene and discovered a further 13 of the vintage weapons before giving the all clear.

As a precaution, the surrounding houses and site were evacuated and Mr Flood, who started work on the project on Monday, said he was shocked to have made the find.

'I was just digging the foundations and I went down to check the level of the foundations and I just saw them there,' he said.

'They looked like pineapples. They were just lying around but the army came in and found more, 19 in total seemingly.

'Some of them had holes through them, so I just shouted to the other workers to get back,' he said.

Mr Flood said the gardaí arrived within minutes and the area was immediately cordoned off.

'We more or less thought they were dead (the grenades) by looking at them but we said we'd just call the guards anyway just in case.

'You just wouldn't be sure,' he said.

A Defence Forces spokesman said the grenades, which he described as non-viable, were removed from the scene but were not being put on display for photographs.