Biblical citations on weapon sights used by New Zealand troops in Afghanistan are "inappropriate" and will be removed, the Defence Force says.

Rifle sights used by Kiwi troops were supplied with references to Bible verses that appear in raised lettering at the end of the stock number.

Markings include "JN8:12", a reference to John 8:12: "When Jesus spoke again to the people, he said, 'I am the light of the world. Whoever follows me will never walk in darkness, but will have the light of life'."

The Defence Force learnt of the citations when The Press contacted it yesterday.

Critics say the inscriptions on the Trijicon Advanced Combat Optical Gunsight, also used by the United States and British military, could be used as an enemy propaganda tool.

Defence Force spokesman Major Kristian Dunne said New Zealand, like other nations, had been caught "unaware" and was unhappy at the revelation.

"It's put us in an uncomfortable situation. We can see how they would cause offence. We are unhappy they didn't make us aware of it."

The Defence Force would talk with the US-based manufacturer and supplier to ensure future orders did not have the inscriptions, he said, and it would remove the letters from existing gunsights.

"They didn't violate any policy but we consider them inappropriate. Everyone has freedoms of religious belief ... It also could be used against us by other religions."

Dunne said the Defence Force had about 260 of the company's gunsights, which were first bought in 2004, and soldiers would continue using them.

"The sights were chosen because they are the best of their kind."

The citations were not on every weapon and were not "overly visible", Dunne said.

Defence Minister Wayne Mapp said the biblical codes were "undesirable" and could be "easily misconstrued".

"They send the wrong sort of message. They cause the same problems as putting slogans on bombs," he said. "We should not be doing anything that might give opponents any propaganda leverage."

The Government had not been aware of the citations, he said.

- © Fairfax NZ News