Rental markets across capital cities remained tight in June as vacancy rates shrank and prices surged, according to the latest figures from SQM Research.

The national vacancy rate has fallen to 1.7% over the month of June, representing the lowest vacancy rate since 2011. Sydney, Melbourne, Adelaide, and Hobart all registered declines in vacancy rates.

Melbourne posted the biggest decline in vacancy rate during the month, from 3.7% to 3.5%. Hobart and Darwin had the lowest vacancy level at 0.4%.

"Rental vacancy rates have fallen in our largest capital cities. Meanwhile there was some further evidence that we have reached the high point in regional occupancy and some relief for local renters may be coming later this year, notwithstanding Sydney’s latest lockdown," said Louis Christopher, managing director at SQM Research.

Given the continued tightness in the rental market, asking rents have increased by 1.8% for houses and 1.7% for units nationwide. Capital cities have recorded more substantial gains, up by 7.7% for houses. However, unit rents were still on a downtrend, falling by 0.5% during the month.

"Rents are now accelerating in our larger capital cities, which may have ramifications for the CPI read in the coming quarters," Christopher said.