According to latest Real Estate Institute of New Zealand figures, Wairarapa's median house price dropped from $250,00 to $242,500 in the month to April, while across the wider Wellington region the median house price rose from $400,000 to $415,980.
Mortgage Link Wairarapa adviser Sam Oldfield said in a "rising interest rate market" it was not uncommon for housing affordability to worsen.
"It is important for everyone, including current mortgage holders and first home buyers, to make sure the interest rate on their mortgage is correct for them, as this can have a big effect on household budgets.
"Where a floating rate works for some people, a fixed rate is more appropriate for others."
In the last few months he had seen a dip in the number of first home buyers, following interest rate rises and the Reserve Bank's lending restrictions introduced in October, which placed a 10 per cent cap on all bank home loans for those with less than 20 per cent deposit.
Nationally, it now takes nearly two-thirds of a median income to pay the mortgage on a $432,250 median-priced house.
The Roost figures were released in the wake of last month's Budget, which was criticised by Labour for offering little to first home buyers.
The sole new home affordability measure was the temporary suspension of tariffs and duties on building products, reducing the cost of a standard new home by about $3500.
Political tensions were further fuelled by the OECD's latest Economic Outlook report, which rated New Zealand house prices the most overvalued in the developed world on a price to rent ratio, and second worst on a price to income ratio.
Labour leader David Cunliffe said property speculators, mortgage restrictions and migration pressures were locking Kiwis out of the "dream of home ownership". APNZ , additional reporting Adam Bennett