A pick-up in demand for residential investment loans may be "unhelpful", the Reserve Bank of Australia cautioned in the minutes of its monetary policy board meeting this month.Lending to housing investors had been increasing for some time in New South Wales, and over the past six months it had also picked up in some other states, the RBA said."While such a pick-up would be unhelpful if it was a result of lenders materially relaxing their lending standards, current evidence indicated that there was little sign of this occurring." The RBA said: "The recent momentum in households' risk appetite and borrowing behaviour warranted close observation," and might, on present trends and cash rate settings, "encourage speculative activity in the housing market."But it concluded that "present conditions in the household sector do not pose a near-term risk to the financial system."The RBA will release its half-yearly assessment of financial stability next week.