Adelaide?s rental market has tightened further, with a vacancy rate below 1% in December, according to the Real Estate Institute of South Australia.

The current vacancy rate of 0.7% compares with an already-tight 1.6% in November. Despite that, the REISA says there is less tenancy demand than a year ago and the lower vacancy has been caused by a reduction of stock in the market - with many rental properties having been sold in the existing strong sales market.

All sectors of the market report a vacancy rate below 1%, except for the northern suburbs with 1.1%. The Adelaide Hills district continues to report zero vacancies.

The REISA says rents continue to rise steadily and any home asking less than $250 a week is highly-soughtafter.