Parliament has passed a bill creating new search, detection, drug-testing and offence provisions to help control contraband in prisons.
"It will deal a major blow to criminals who have been able to continue running their crime businesses from behind bars and who have used smuggled cellphones to intimidate people on the outside," said Corrections Minister Judith Collins.
The Corrections Amendment Bill (No 2) was introduced by the previous government but did not pass before the election.
It will increase controls over prisoners' communications with the outside world and their ability to commit crime from inside prison.
It enables mail to be screened and introduces zero tolerance to staff that pass contraband to prisoners.
"The passage of this bill is long overdue," Ms Collins said.
"The previous government promised to clamp down on contraband but, like so many other law and order bills, it allowed this bill to languish on the order paper for months."
