Christchurch Men's Prison has thwarted three attempts to smuggle in drugs this week.
Acting prison manager Trevor Saunders says the most significant find was a prisoner internally concealing 33 grams of cannabis and 3 grams of a white powder suspected to be heroin.
He says the prisoner was acting suspiciously, so was placed in a cell without a wash basin or toilet until he passed the drugs.
Mr Saunders says staff also found a tennis ball thrown into the prison stuffed with 21 grams of cannabis, and a visitor hiding a small amount of drugs.
