Tax concessions are leading residential investors to pour excessive amounts of money into the wrong types of dwellings, two leading academics say.

Pointing to data from the most recent census in 2011 showing that around 120,000 dwellings lay vacant in the Sydney metropolitan area alone and that the number of unused and under-used dwellings (including those used for short term rental accommodation) amounted to 238,000 in Sydney and 230,000 in Melbourne, University…