People prefer to black market tobacco are easier to have bad lungs and other physical diseases than those smoking the legal variety, a new study said.

The survey, released at a national public health conference in Brisbane Monday, said smokers of so-called chop-chop widely believe the unbranded loose tobacco is "healthier" because it does not contain the same chemicals as commercial cigarettes.

"We now have a fairly good indication that that's really not the case," Dr. Campbell Aitken, from the Burnet Institute in Melbourne, said at the conference.

"In fact people who smoke chop-chop seem to have significantly worse health than smokers of licit tobacco who, as we well know, already have worse health than non-smokers," the Australian Associated Press quoted Aitken as saying.

Sold under the counter through tobacconists and markets in poorer suburbs and on the Internet, chop-chop is about a quarter the price of commercial tobacco.

The survey showed that about seven percent of Australian smokers usually smoke this variety, while a quarter said they had tried it at least once.

Aitken said this estimate was conservative as those believed to most widely smoke the product, younger people and the homeless, were poorly represented in the phone survey of 1,500 smokers.

Those who had smoked it had started smoking at an earlier age, smoked more heavily and had worse mental health, physical health, and poorer social functioning, the study said.

The survey also called for a targeted campaign that urges smokers away from illicit tobacco but, says Dr. Aitken, this would not be ideal.

A tax office report from 2004/05 estimated that the illegal tobacco industry cost the country 98 million Australian dollars (94 million US dollars) annually - a 56 percent increase on three years earlier.

(Xinhua News Agency July 8, 2008)