SINGAPORE - The International Council on Monuments and Sites (Icomos) Singapore has issued a strongly worded statement against the authorities' decision to demolish and reconstruct part of the conserved Ellison Building.

The council, part of the international Icomos Unesco advisory body, said it was "deeply disturbed by the authorities' disregard for the heritage value of this building and the lack of transparency behind this decision".

Part of the 1924 building at the corner of Selegie Road and Bukit Timah Road will be making way for the construction of the North-South Corridor - despite the Urban Redevelopment Authority's (URA) conservation gazette.

Three of the building's 16 two-storey units will be torn down. The affected units - 235, 237 and 239 - are along the building's curved facade.

The Land Transport Authority (LTA) said previously it would reconstruct and reinstate the affected part of the government-owned building to its original architectural design, under the URA's guidance, once the tunnel is completed in 2026.

Construction of the 21.5km underground corridor, using the traditional "cut and cover" method, is expected to take place progressively from next year.

The authorities had described the decision as an "exceptional course of action" that was taken after considerable study and deliberation. They said it was a last resort after concluding that it was not possible to completely avoid the building "in order to realise an important national infrastructure".

Icomos Singapore said the decision is problematic and regressive on three fronts.

First, it said that conservation must act as a deterrent against destruction.

"The public must assume that a conserved building is in fact protected, and not an inconvenience to be done away with when it is deemed to hamper planning dictates. The decision to demolish the three shophouses sets a highly unhealthy precedent.

"It negates the critical role of heritage conservation in Singapore's national planning agenda and undermines decades of painstaking efforts by state agencies, building owners, heritage stakeholders, professionals and builders, and the progress in conservation achieved so far."

Second, it noted there was no evidence if the authorities had consulted with stakeholders, engaged with experts to explore alternative solutions, or undertaken a heritage impact assessment.

Third, reconstruction is an option that is explored only in situations such as warfare or natural calamities that have damaged significant structures and sites, as part of the healing process of a city and its inhabitants.

Icomos Singapore, which had conducted historical research and reviewed Singapore's nomination dossier for the Botanic Gardens' Unesco bid to be a World Heritage site, said: "The proposed partial demolition and reconstruction is a conscious planning decision. In this case, the decision to reconstruct appears to be little more than a convenient and expedient resolution that short circuits the due processes described earlier."

It is the second organisation to have spoken out against the decision. The Singapore Heritage Society strongly urged the authorities to explore other options in a statement to The Straits Times two weeks ago.