Official correspondence shows that a plan to ban smoking in prisons went before the minister responsible for tobacco control, only hours before the public found out about it.
But documents obtained by Radio New Zealand under the Official Information Act show Corrections Minister Judith Collins was briefed on the policy change more than a month beforehand.
Associate Health Minister Tariana Turia received the papers on the morning of the announcement in late June.
Mrs Turia wrote to Ms Collins pointing out that the new policy fell directly within her portfolio responsibilities and asked to be kept informed in the future.
In reply, Ms Collins said consultation with Mrs Turia was curtailed and the ban made public to stop any misinformation being spread.
Ms Collins said she was disappointed an opportunity for their two departments to be seen to be working together was missed.