Office prices and rental rates in Perth’s business district will fall as much as 50% by 2013 from last year’s highs as mining projects stall and new blocks are completed, real-estate forecasters and agents said.

Vacancies in the center have risen from a record low of 0.3% last June, among the tightest in the world, to about 6 percent and will jump to 16% by mid-2010, said Lee Walker, at Sydney-based forecaster BIS Shrapnel. The rate will peak in 2013, with average prime rents dropping to A$360 ($286) per square meter from A$720 now, he said.