An inmate with a stash of meth, cannabis bud and oil, and an acid tab was caught trying to smuggle the drugs into prison after a period of compassionate leave.

The planned drug run was thwarted by the Department of Corrections after it intercepted a series of phone calls between an inmate at Whanganui's Kaitoke Prison and Taranaki man Daniel Alan Couchman.

The pair spoke over the phone a number of times in April last year, discussing their plans to sell cannabis.

Couchman, 27, said he had around a pound of weed in the boot of a car at a Stratford property and agreed to sell an ounce of the drug and use the proceeds to top up the inmate's "account".

The calls were monitored by Corrections staff who subsequently reported the matter to police.

The following month, in May last year, Couchman and the inmate conspired to supply an associate, who was also an inmate at Kaitoke Prison, with cannabis and class A drugs.

The associate had been granted a day of compassionate leave and while out he met with Couchman who gave him 17.89g of cannabis bud, 9.11g of cannabis oil, 1.36g of methamphetamine and a single tab of acid.

When he returned to prison, he was searched by Corrections staff and taken to Whanganui Hospital for an internal examination, leading to the discovery of the drugs.

Couchman and the inmate, to whom he made the phone calls, were charged with conspiring to sell cannabis and supply of meth and cannabis.

Couchman has admitted the charges but the inmate is yet to enter pleas.

In unrelated offending, Couchman has also pleaded guilty to supplying meth and possession of cannabis.

He appeared in New Plymouth District Court today for sentence on the drug charges but the matter was adjourned after defence lawyer Paul Keegan said Couchman was now facing two further prosecutions.

Judge Gregory Hikaka remanded him into custody at Kaitoke Prison until May 5 when he will return to court on all matters.