Asbestos has been discovered in building materials at the old Royal Hobart Hospital (RHH), and health workers say they want new building instead of another patch-up.

Tasmania’s Health and Community Services Union says its members and the safety of the patient community are at risk if the RHH redevelopment works continue in the presence of asbestos.

Local newspapers say that an assessment is under way to ascertain the exact level of asbestos in buildings which were going to be knocked down.

Reports claim that an assessment report conducted by a local asbestos safety company last December showed that the deadly material was present in seven of the eight buildings.

Assessors allegedly found asbestos in window putty, pipe work, vinyl floor and several other locations.

For the most part, materials containing asbestos are not dangerous until they are disturbed.

Asbestos particles can enter the lungs and lead to a range of negative health effects, mesothelioma being the best-known.

The substance must be handled under extremely strict safety procedures, and it is expected that the discovery of the hazardous material might delay the project.