The pair were caught by armed guards last August as they sprinted across a grass plain outside the prison in western NSW, according to footage aired on Channel 7 on Monday night.

Guards found five tennis balls filled with ice, marijuana, mobile phones and prescription drugs.

The men were planning to throw the tennis balls over the fence to an "established" inmate.

Instead, they ended up behind bars themselves.

"It was broad daylight, they were very motivated, they were actually engaged by one of the more established criminals," general manager of Wellington Correctional Centre Brad Peebles said.

A lengthy covert operation resulted in the two men being apprehended and charged with numerous drug supply offences.

The men, aged 27 and 34, received minimum prison sentences of two years and five months and two years respectively.

"The operation was well-planned and involved intensive surveillance over a period of weeks," Corrective Services Commissioner Peter Severin said at the time of the arrests last year.

On Monday night, Channel 7 interviewed staff at Wellington prison who said they used a special operations group, including a canine, to investigate attempts to bring in contraband.

Everyday items like mobile phones and cigarettes are often sold for thousands of dollars within prison.

A razor was allegedly used recently by an inmate in Kempsey prison to carve an Islamic State slogan into another inmate's head.

"Anything can happen, we don't know what we're going into. Every day we walk in, we don't know what we're going to be responding to," one prison officer told Channel 7.