Traders say the introduction of plain-packaged cigarettes is a nightmare for those serving customers and is unlikely to stop people smoking.

The new cigarette packets have started appearing in Victorian supermarkets following the halt of old-style package manufacturing at major tobacco factories belonging to Philip Morris in Melbourne and British America Tobacco in Sydney on October 1.

Under the federal government-imposed regulations, stores can still legally sell the old packets until December 1.

Australia became the first country in the world to introduce plain packaging this year after a lengthy legal battle with tobacco companies that challenged the legislation on constitutional grounds.

The August High Court decision that allowed the law to pass has been described by the World Health Organisation as a ''landmark'' ruling that will inspire other countries to follow suit.

But 7-Eleven worker Reece Cheng told The Age the plain packets create confusion for shop owners and customers alike.

''About 30 to 40 per cent of the cigarettes have already moved to the new packaging. It's very confusing I have to say because the new packaging is all the same. ''Normally we memorise the whole display by the colours because people always ask for the colours.''

Mr Cheng said cigarette sales make up a large proportion of all profit but he doubted the new packaging would have any discernible impact on smoking rates.

''It won't make much difference at all. It goes into the pocket, they're not going to look at the packet while they smoke. The only thing that would make a difference would be the cost of the packet, if they pushed it above $20 a packet.''

The new packets have all branding removed and are required by law to be a uniform olive colour featuring prominent health warnings and a simple brand name. Henry Bajwa of NightOwl Convenience said he is finding the new packaging a bit difficult but hopes it will become easier in time.

''Some people see the pictures and think maybe it's not good, so maybe it will help stop them. But I think people who are going to smoke are still going to smoke.''

Quit Victoria executive director Fiona Sharkie said plain packaging was primarily designed to deter young people from smoking rather than encourage existing smokers to quit.

''One of the main objectives of this legislation was to make cigarettes less appealing to young people,'' Ms Sharkie said.

She said that meant plain packaging was unlikely to impact retailers straight away.

''In the 30 years we've been campaigning for things like bans on smoking at bars and restaurants people have been fearing it will send them out of business.

''Unfortunately, it takes a lot longer for people to quit [even though] 80 per cent of smokers tell us they want to.''

A teen smoker who spoke with The Age said she was ''annoyed'' but not deterred by the plain packaging.

''I got one of those packets and it tasted different.''

Australian Institute of Health and Welfare statistics show 14.9 per cent of Victorians over 14 are daily smokers, just below the nationwide average of 15.1 per cent. Smoking is believed to cause about 6 million deaths a year worldwide.- With

JULIA MEDEW, NIKITA McINNES