A cigarette company has asked appeal judges to block rules intended to ban the open display of tobacco products in shops.
Imperial Tobacco claimed that the Scottish Parliament had no legal right to restrict the open sale of its products.
It was appealing against an earlier ruling that none of its challenges were "well founded".
Legal action has already delayed moves to enforce the new law.
The attempt to clear cigarettes from the shelves of shops was part of the Tobacco and Primary Medical Services Act, passed by the Scottish Parliament more than a year ago.
The first stage of the ban, applying to major retailers such as supermarkets, should have come into force in October of last year.
Imperial Tobacco, which makes brands such as Lambert and Butler, went to the Court of Session seeking a judicial review of the MSPs' decision.
That move delayed the implementation of the regulations, although Lord Bracadale subsequently ruled against the company.
At the Court of Session, Imperial Tobacco has challenged that decision.
Mike Jones QC continued to put their case that the Scottish Parliament was acting beyond its powers when it enacted the legislation.
Judges at the Court of Session are expected to give their decision on the appeal at a later date.
Two weeks ago, another aspect of the new rules survived a legal challenge.
Sinclair Collis, Britain's largest operator of cigarette vending machines, failed in an attempt to overturn a ban on their use.
The vending machine operator is a wholly-owned subsidiary of Imperial Tobacco.
Smoking and cancer
In spite of the opposition from retailers and cigarette manufacturers, the new restrictions were welcomed by health and anti-smoking organisations.
The Scottish government had argued that action was needed to prevent young people taking up smoking.
A spokesman said: "Each year in Scotland 15,000 children and young people start smoking and a child who starts smoking at 15 or younger is three times more likely to die of cancer as a result than someone who starts smoking in their mid-20s."
Figures released by the NHS in Scotland showed that less than half of those it helped to give up smoking in 2010 were still off cigarettes after a month.
Almost 80,000 people attempted to quit the habit. Around 31,000 said they had been successful.
These figures were up slightly on the previous year.
The Scottish health minister, Michael Matheson, welcomed the improvement and said he believed that the health service would make further progress in future.