Wellington, Sept 28 NZPA - Tobacco companies are undermining the law and public health policy by not following graphic warning regulations, a researcher says.

A study of purchased and discarded cigarette packs showed the regulations were not being "appropriately followed", Otago University marketing professor Janet Hoek said.

Graphic warnings became mandatory in August 2008 and tobacco companies are required to evenly distribute various images over all cigarette packs.

Dr Hoek said the most offensive graphics were printed less frequently than other "less disturbing" images.

"These (more offensive) images included graphics of smokers' external body parts, such as a diseased mouth or eye, or gangrenous toes," she said.

"This is of concern as it undercuts the law and public health policy, which aims to reduce the serious health impact of smoking."

About 5000 New Zealanders die of smoking related illnesses each year.

The most common image featured on both purchased and discarded packs was a body with a toe-tag.

"Tobacco companies have made it clear they dislike the new regulations on graphic health warnings, and these findings suggest they may be trying to minimise the impact of the new law."

Dr Hoek said tobacco companies should be required to submit the warnings' print run information.