Church leaders are to offer a ‘substantial’ reward for the return of the preserved heart of Dublin’s patrol saint Laurence O’Toole.

News of the reward comes as Irish police look to trace two foreigners who were caught on camera in the city’s Christchurch cathedral at the time of the theft.

Details of the reward are expected to be announced on Monday, nine days after the 800-year-old heart was stolen from the Cathedral.

Police officers are keen to speak to two men, believed to be foreign nationals, who are visible on CCTV footage from the scene.

The men were wearing hats and tried to avoid the CCTV cameras.

When asked to remove their hats by cathedral staff, they refused to do so.

Police sources say one of them was carrying a backpack and when they left, one of them carried the backpack at knee-height.

They were later seen running away from the building.

Officers are currently enhancing video images of the suspects and want to interview the men.

“The men on the camera footage could be crucial to our investigation and, at this stage, we are anxious to identify them, if only to eliminate them from our inquiries,” one officer told the Sunday Independent newspaper.

Thieves stole the preserved heart of St Laurence O'Toole, Dublin's patron saint, from Christ Church Cathedral on Saturday morning.