Apple's new seven-storey mega shop is being built on the former site of Madrid’s 600-year-old Buen Suceso hospital, once used to treat plague victims.

The technology giant's renovation of Puerta del Sol's symbolic Tío Pepe building led to the discovery of the foundations of the ancient building last week.

Back in 2009, railway construction workers unearthed the remains of an historical church located next to the hospital, both buildings carried the same name.

"We’re not surprised to find these remains because we knew they could be there", the director of the Madrid Heritage Department, Jaime Ignacio Muñoz of the Popular Party, told Spanish daily El País.

Although diggers at the Buen Suceso Church discovered remains from burials and executions from the 19^th century Napeolonic Wars between Spain and France, no bones have yet been found at the recently unearthed hospital.

Madrid's emblematic Tío Pepe building is the new site of Apple flagship store in Spain. Photo: librarygroover/Flickr

Buen Suceso Hospital is believed to have been demolished in 1854 during a revamp of the capital's main square, Puerta del Sol.

The church's remains, which delayed the railway improvements for nearly a year in 2009, have been preserved behind protective glass in the mezzanine of the station ever since.

Muñoz has told Apple they will only have to change their basement plans and "symbolically" trace the outline of these newly discovered walls.

This means the tech giant will not have to postpone the opening of its new 6,000-square-metre store this Christmas.