Chrissie Swan referred to them as the "not really smokers".
They're also known as 'social smokers' - the people who might sneak the odd cigarette in down at the pub with mates on the weekend.
Because they don't smoke all the time, they generally think they are in control of their habit, but that is not necessarily the case, an expert in the psychology of addiction says.
Dr Lee Hogarth, a senior lecturer in psychology at the University of NSW, said about five per cent of smokers maintained an infrequent smoking habit over long periods of time, including people who had a few social cigarettes at the pub on the weekend.
"Such people tend to call themselves non-addicts, but that's based on the idea that what distinguishes addiction from non-addiction is frequency. That's not necessarily true," he said.
"If they were put to the test, these people would probably classify themselves as non-smokers, or light smokers. It's just a semantic distinction really.
"It's when you start using it as a legal justification or a moral argument, such as why [Swan] continues to smoke despite being pregnant, that it really carries some weight."
During a tearful interview on her radio show on Wednesday, Swan said she had been caught smoking by paparazzi during her third pregnancy, forcing her to come clean to her family and husband.
Despite quitting smoking during her previous two pregnancies, Swan said she had started sneaking a few cigarettes about a year ago.
"I was what I would call a 'not really smoker'," Swan said.
"I never smoked at home and I never smoked around my family. I'd just sneak a few here and there and I know I'm not alone in this. Mainly I would do it in the car, in fact, I would only do it in the car when I was certain that I was alone."
Dr Hogarth said the street term for a person who maintained low rates of drug use over an extended period of time was "chipper", which originated among opiate addicts in New York. The first study of them was conducted in the mid 1970s.
Dr Hogarth said a large chunk of the present day population were alcohol chippers.
"Loads of people drink only at the weekend, and they don't all progress to permanent alcoholism. A large chunk of the population can be considered alcohol chippers," he said.
However these people who drank or smoked only on weekends could be considered addicts if they knew it was doing them harm and couldn't stop.
Criteria for clinically diagnosing someone as an addict includes determining whether a person had developed a tolerance to the drug; had difficulty in cutting down; suffered withdrawal; displaced healthy or other activities with drug use; and continued to use drugs despite knowing they had a problem.
"That continued use, despite knowledge of problem, is normally the one that is the rule of thumb," Dr Hogarth said.
"[Swan] is clearly addicted by that criteria. In terms of knowledge of the long-term health consequences to the foetus/baby, it's clear."
Weekend smokers or drinkers who fulfilled the above criteria could also be classified as addicts.
Dr Hogarth said if people were stressed or depressed, they often had much poorer self control and were much more likely to relapse.
It also comes down to a person's physical traits.
"Dopamine encodes one's experience of reward, and if your dopamine system is highly activated by a drug of abuse, then you experience it as being more rewarding and you do it more frequently as a proportion of your behaviour," Dr Hogarth said.
"If it's less activated, you do it less frequently.
"It's not a matter of choice so much, it's a matter of constitution."