Reserve Bank of New Zealand governor Graeme Wheeler has given his first media interview in more than a year in the job, defending the bank's controversial limit on low deposit lending and rejecting calls for exemptions for new construction loans.Wheeler told Radio New Zealand there was anecdotal evidence the speed limit on high loan-to-valuation ratio loans was starting to have an impact, but it would take three to six months for data to show its impact more clearly. The limit was imposed on October 1, but banks have been slowing such lending since late July when the bank warned the limit was coming."We are certainly seeing fewer special offers from banks. Banks have increased low equity premia in their loan terms and they're cutting back lending to those on low deposits, and there are fewer people attending some of the open days," Wheeler said."There's a lot of anecdotes to suggest they're having some impact, but we won't know for sure in terms of the data for another three to six months," he said.Wheeler also played down the need for exemptions for loans for new home construction.He said the bank did not believe the speed limit was a major impediment for new home building because demand for homes was so strong and there were still some low deposit loans being written. The cost of building a new home was also more attractive relative to the cost of existing homes, he said."We'll certainly keep talking to the banks, but at this point we don't see a strong case for exempting new housing," he said.Earlier this month the Registered Master Builders Federation warned the speed limit could reduce new home building by as much as 3000 per year and it called for an exemption for new home building, given both the Reserve Bank and the Government believe house price inflation is driven at least partly by supply shortages in the two main housing markets of Auckland and Christchurch.