Firms' margins were squeezed in the December quarter as the prices they paid rose 0.5 per cent but the prices they received rose just 0.1 per cent.
Compared with a year earlier, input producer prices rose 4.2 per cent and output prices 3.4 per cent, Statistics New Zealand said.
Infometrics managing director Gareth Kiernan said the economic environment of global uncertainty and a patchy domestic economy were squeezing businesses' margins and making it hard for them to pass on even the modest cost increases they faced.
Manufacturers saw input costs climb 1 per cent in the quarter but their output prices rose just 0.1 per cent.
For the construction sector the gap was between a 0.5 per cent increase on the inputs side and a 0.3 per cent rise in output prices.