The Australian government has commenced on Tuesday the defence of its cigarette plain-packaging law, which experts said could be adopted by other nations as an effective model for their anti-smoking campaigns.

The new regulation will bar tobacco companies from printing cigarette brands on every pack, forcing them instead to use a drab olive-green paper on the outer packaging with bold and graphic health warnings that highlight the ill-effects of cigarettes smoking.

If the legal contest ended in favour of the government, the new laws will take effect as scheduled on December 2012.

Federal authorities, media reports said, have been constantly harping on the health hazards that come with the habit, which it said kills thousands of Aussies each year and jacks up the health care expenditures of states and national governments.

But legal challenges have been filed before the Australian High Court by giant tobacco firms, composed of British American Tobacco (BAT), Philip Morris, Imperial Tobacco Australia and Japan Tobacco International, arguing that the measures were unconstitutional and infringe on their trademark rights.

Attorney-General Nicola Roxon, however, is convinced she's defending an air-tight case, telling media people on Tuesday that "that we have taken careful advice, that we have a strong case and that will be argued by the Solicitor-General today and in the coming days in this court."

"We went into this policy and introduction of the legislation with our eyes open, knowing that tobacco companies have a history of litigation," Agence France Presse (AFP) quoted Ms Roxon as saying in Canberra.

She has been in the forefront of the fight while serving as the country's health minister, overseeing the laws approval before the Parliament late last year.

The federal government, she added, is dead-bent on seeing through the implementation of the laws in order to eliminate tobacco-related diseases and deaths and to cut down unnecessary health spending.

"Our government is determined to take this action because we think it can save lives ... We think it can have a positive impact on the budget by reducing some of the expenditure that is spent each and every year in treating tobacco related illness," Ms Roxon said.

Tobacco companies were not contesting the health aspect of the new laws but were focusing on the likelihood that the government will practically kill their brand names by disallowing their on cigarette packs that will be sold in the market.

Such measures were in violation of the constitution, the companies said in seeking compensation for the damages that the laws will cause to their operations.

"The packet (under the legislation) has become a servant of the commonwealth's purpose ... It is a vital space (on packs) because it's the last space available," Philip Morris lawyer Alan Archibald was quoted by the Australian Associated Press (AAP) as saying before the High Court on Tuesday.

Also, BAT spokesman Scott McIntyre has announced in advance that "we will defend our property on behalf of our shareholders as any company would."

But Ms Roxon insisted that there is nothing unlawful in government policies, adding that "over many decades we've taken steps to introduce tobacco-control measures and this is the next step."

"Regulating the way tobacco is sold in Australia is something that is lawful for any parliament and any government to do," the attorney-general asserted.

Solicitor-General Stephen Gageler will present the government side on Wednesday and parties will be given until Thursday to argue their cases but a decision from the High Court is not expected until the second half of 2012, according to AAP.