In the first month of the ban, 208 incidents were reported nationally. This dropped to 172 in April.
January had the least number of smoking-related contraband finds, with 152 incidents recorded.
Smoking-related contraband includes tobacco, cigarettes, filters, cigarette papers, matches and lighters.
Prison Services general manager Jeanette Burns said that in most cases, contraband items were found on inmates or visitors before they entered the prison.
The start of the ban followed a year-long campaign to help prisoners quit smoking.
The information also showed that in June 2010 when that campaign started, about 5600 prisoners making up 67 per cent of the prison population, smoked.
"By the time the ban was implemented, all prisoners had been assessed, and the majority had taken up nicotine replacement therapy (NRT)," Ms Burns said.
She said that between November 1 and May 22, 8038 new prisoners were questioned about their smoking status and 70 per cent said they were smokers. Of those, 4177 prisoners elected to start NRT.
"All prisoners are questioned about their smoking status as part of their reception evaluation. If identified as tobacco smokers they are assessed for and offered NRT in the form of patches or lozenges," said Ms Burns.
NRT is funded by the Ministry of Health and no cost is incurred by the Department of Corrections.
Last month Corrections Minister Anne Tolley said $65 million had been "reprioritised" to expand drug and alcohol treatment in prisons and the community.
The funding would enable Corrections to treat 33,100 more offenders with addiction problems.
She said the first year of the smoking ban was a "real success" and staff and inmates had seen great benefits.
"Safety is much improved, with offenders no longer having access to lighters and matches. This has meant a 72 per cent reduction in fire-related incidents."
"It has also removed the opportunity for prisoners to use lighters to melt plastic into dangerous weapons."
Air quality had improved and the threat of harm from passive smoking removed.
SMUGGLED GOODS
Prisons with highest number of finds:
Men's prisons
* 1 Waikeria prison - 246 incidents
* 2 Christchurch prison - 193
* 3 Hawkes Bay prison - 173
* 4 Rimutaka prison - 171
* 5 Spring Hill corrections facility - 163
Women's prisons
* 1 Auckland region women's corrections facility - 72
* 2 Christchurch women's prison - 61
* 3 Arohata prison - 30
Prison with lowest number of contraband finds
* Wellington prison - 14.