Dairy owners are worried the latest tobacco price hike could put their safety at risk.

Business owners said they were fearful that the tobacco tax increase would mean customers who could not afford the product but who could not quit would become desperate and aggressive.

On January 1 the third tobacco tax increase in three years hiked cigarette prices by 10 per cent, pushing the average price of a cigarette pack up to about $20.

The Government announced in 2012 that increases would take place each year for four years as part of the Smokefree 2025 goal.

Business owners in Palmerston North fear an increase in robberies as a result of the tax increase.

One dairy owner she had a knife pulled on her a few months ago. She said the man demanded cigarettes.

She feared it would become more common, but they had security measures in place.

"There is nothing more we can do. Just hope for the best."

Dairy owner Manhar Patel said they had had cigarettes stolen in the past. He was afraid smokers might become desperate because they could no longer afford the cigarettes.

"It will happen more. "Some people, they can't stop [smoking]. It's a scary time."

He said he had not been threatened, yet.

"Those who are really addicted will still smoke," Palmerston North dairy owner Frank Hsu said.

Most shop owners had security systems in place.

Patel said sales of 50-gram tobacco had dropped during the past few years because it was too expensive for people. "People see it's about $75 for tobacco and then add on papers and a lighter, it's just too much."

Some customers had expressed a desire to quit. Others had dropped from a 30-packet to a 20-packet.

"I'm not making money off cigarettes."

Hsu said: "Our cigarette margin is really low. If they give up cigarettes they will have more money for other stuff."

In the MidCentral District Health Board catchment, the number of pack-a-day adult smokers has dropped by 24 per cent since 2006.