HERE’S a #facepalm moment if ever there was one.

So it turns out we’ve been wrong for two years about how many people have been buying their first home - with the figures set to surge 20 per cent in one day.

The Australian Bureau of Statistics made the announcement this morning after it found some lenders were not including figures for first home buyers who did not receive first homeowner grants.

Queensland and New South Wales have been particularly affected, with the number of first home buyers set to rise 20 per cent after an investigation revealed some lenders had under-reported figures since October 2012.

The tables now show that 38,747 dwellings had been financed for first home buyers in Queensland from October 2012 to November last year, which could mean that over 7,000 first home buyers were not counted previously.

ABS’ Jacky Hodges said first homebuyer loan figures had been published since the early 1990s with the bureau noticing a recent drop-off in numbers.

“Initially we thought the fall off in first homebuyer loans over the last two years was due to reduced affordability arising from changes in grants, rising house prices, increased investment housing loan activity and general economic conditions,” she said.

“However, subsequent analysis and follow-up with lenders has confirmed that the drop was partly due to under-reporting by some lenders.”

She said ABS and the Australian Prudential Regulation Authority - which collects the first homebuyer loan data for the ABS - would ensure all loans to first home buyers were recorded in future, whether they got a grant or not.

The next housing finance data for the country was due for release next Wednesday with first home buyers defined as “persons entering the home ownership market as owner-occupiers for the first time”.

ABS said the total value of home lending was separately reported and would not be affected.

The First Home Owner Grant was introduced on July 1, 2000 as a national scheme funded and administered by states and territories, giving a one-off grant to eligible first homeowners.

“Until October 2012, all first home buyers were eligible for the grant regardless of whether they bought a new or an established home,” according to ABS.

The under-reporting began to occur when grants were only applied to newly constructed homes in Queensland and New South Wales from October 2012, Victoria from July 2013, ACT from September 2013, South Australia and Tasmania from July last year.

“Loans to first home buyers were therefore underestimated in these states from the dates specified due to some lenders under-reporting. Other lenders have reported correctly throughout.”

ABS did not point the finger at any particular lender.