The AFG Mortgage Index revealed that the average mortgage in WA rose to $337,000 in January - an increase of 3.5% from December. In contrast, mortgages in NSW fell to the current average of $351,000. This narrowed the gap in value between the two states to just $14,000 - the closest ever recorded by AFG. "In the past year, we've seen the size of NSW mortgages softening while WA has soared ahead by about $50,000. It would come as no great surprise to see WA move ahead of NSW in the next few months," said Mark Hewitt, general manager of sales and operations at AFG. "Even though the WA market has shown it's no longer immune to rate rises, the dynamics supporting it are still much stronger than other states." The mining boom in the western state has pushed property prices up by 37% in the last 12 months according to the latest data from the Australian Bureau of Statistics. While rising prices and falling affordability have kept many first homebuyers at bay, investors continue to bet on the property market with WA retaining the highest proportion (43%) of investors thanks to the buoyant rental market.