Ministers could be facing legal challenges over Holyrood's proposed smoking ban.
Ministers have defended the smoking ban proposals
But Health minister Andy Kerr has rejected reports that the cabinet faces a climbdown on the proposals to axe lighting up in enclosed public places.
Mr Kerr said on Sunday that he believed the planned bill would not contravene Article 8 of the European Convention on Human Rights.
The legislation is expected to be unveiled next week.
Mr Kerr said: "People can bring their own cases if they see the need to do so. We are certainly clear about our abilities to do what we want to do."
But opposition parties stressed that any new law must be applied fairly if it is to work.
The Scottish National Party's health spokeswoman, Shona Robison, said: "It must apply equally to private clubs.
"There would be an inherent unfairness with the system if it did not, and that wouldn't be fair on the licensed trade."
Smokers will be forced outside pubs to light up
She added: "So the minister has to find a way to make sure it's enforceable."
Conservative health spokesman David Davidson said: "The proposals are wide open to a legal challenge."
Paul Waterson, of the Scottish Licensed Trade Association, insisted: "We believe the executive hasn't thought through the legislation and we will be looking at it very closely when it's published."