Labour is accusing the Government of failing to deliver on a promise to allow women to spend more time in hospital after the birth of their first babies.
In 2009, Health Minister Tony Ryall, allocated $38 million over four years to help new mothers to stay longer.
Labour health spokesperson Annette King called for an audit, saying she wants to know where the funding has gone.
She issued figures that show there had been very little change to the length of maternity stays since the announcement, with an average stay of 2.25 days for new mothers after birth.
But associate health minister Jo Goodhew said the figures may not accurately reflect the results of the policy, as not all district health boards keep separate records for first time mothers.
And, she said, longer stays were only ever intended for those who felt they needed extra support, rather than every woman.