Declining interest rates and rising income have boosted housing affordability across the nation in all but one state according to a new report.

Released earlier this week, the Adelaide Bank and Real Estate Institute of Australia (REIA) Housing Affordability Report revealed that nationally the proportion of income required to meet loan repayments decreased by 0.5% to 30.3% over the June quarter.

Compared to the June quarter of 2014, the proportion of income needed to meet loan repayments has decreased even further, by 0.6%.

Compared to the previous quarter, all states and territories saw affordability improve, except for New South Wales where proportion increased by 0.6%.

New South Wales remained the least affordable state for homebuyers with the proportion of income required to meet loan repayments 5.3% above the national average.

The Australian Capital Territory is still the most affordable state or territory in which to buy a home with the figure sitting at 19.5%.

According to the report, the biggest improvers in terms of affordability over the June quarter were the Northern Territory, where the proportion of income required to meet loan repayments decreased by 2.8% to 24.9% and Western Australia where the proportion decreased by 2.1% to 22.9%.

Over the June quarter, with the exception of Tasmania and the Northern Territory, all states and territories recorded increases in the number of loans to first home buyers. The largest rise was seen in the Australian Capital Territory where the figure increased by 20.9%.

The average loan size to first home buyers increased 3.9% over the June quarter and by 2.9% compared to the same time last year, to $335,400.

Over the quarter, the average loan size to first home buyers increased in all the states and territories with the exception of South Australia. The largest increase was seen in New South Wales.

The total number of loans (excluding refinancing) increased 10.5% over the quarter but was 1.9% lower compared to the June quarter of 2014, to 103,500.

Over the quarter, all states and territories had increases with the biggest rise recorded in the Australian Capital Territory, up by 14.8%

Over the first quarter of 2015, the average loan size increased 0.2%, to $359,630. This represents an increase of 5.2% compared to a year earlier.