Gardaí are investigating an attempted robbery in Dublin in which the family of an An Post employee was held hostage overnight.

At least four armed and masked men forced their way into the home of Mails Operations Director Liam O'Sullivan in Co Kildare at around 9.30pm last night.

They took his wife and mother of their two children hostage.

At approximately 11pm they took the woman from the house. It is believed she was taken to somewhere near Rolestown in north Co Dublin.

Mr O'Sullivan and the children were held in the house overnight.

They then told him to go to work at the GPO, take out over €100,000 in cash and leave it for them at a designated location.

The woman managed to free herself just after 9am this morning and contacted gardaí.

A garda operation was put in place and no money was handed over to the gang.

An Post said this afternoon that everyone was safe and the matter was in the hands of the gardaí.

Appeal for information

Gardaí have appealed for the public's assistance in tracing the gang's movements.

They want to speak to anyone who may have seen anything suspicious in Fennore, Co Kildare and Rolestown, Co Dublin, as well as around the GPO, last night and this morning.

Gardaí are also seeking information on two cars they believe were used in the kidnapping; a silver Honda CRV (05 DL 4275) and a silver Mercedes (11 D 13049).

The Mercedes was found burnt out near Rolestown.

Anyone with information is asked to contact at Newbridge Garda Station on 045 440180, the Garda Confidential line on 1800 666 111 or any garda station.

The Irish Post Masters Union condemned the gang's actions and sympathised with Mr O'Sullivan and his family on their ordeal.

The union said the vast majority of An Post employees do not have access to cash and it appears in this case that the agreed protocols set up to tackle this type of crime worked.