More than 25 breaches in the smoking ban have been reported by councils across Wales in the last five weeks, a BBC survey has discovered.
Wales's smoking ban came in at the start of April
Several written warnings have been issued since the ban was brought in on 2 April, however no fixed penalty notices have yet been handed out.
Officers at Powys council said they had visited 464 premises and issued 11 written warnings.
However, some businesses have said the ban has led to a drop in profits.
Responding to the BBC Wales survey, a spokesman for Blaenau Gwent said five warnings had been written, while Pembrokeshire and Neath Port Talbot officers have each issued four written warnings.
Torfaen council said it had visited 490 premises and was investigating "a small number" of breaches, while Merthyr reported two breaches.
Cardiff council said it had visited 842 premises but did not report any breaches.
Meanwhile, in Ceredigion, a spokesman said one written warning had been sent to the proprietor of a licensed premises.
And Flintshire council said it had dealt with some problems with external smoking shelters, while Conwy council said it had issued advice about smoking shelters and signage.
Environmental Health Officer Eleri Sewell said that the good weather in April had helped the ban settle in.
"A lot of people are dreading the bad weather - they think it is really going to affect the businesses," she said.
"But I think that, by that time, a lot of people will be used to the ban, they will be used to going outside and most places have the shelters now as well."
Council enforcement officers can give out fixed penalty notices of £50 to people who they believe are smoking or have smoked. If it goes to court, the maximum fine is £200.
Premises can also break the law by failing to display no-smoking signs (£200 fixed penalty, maximum fine £1,000).
Premises can also be fined for failing to prevent smoking in a smoke-free place, up to £2,500.
And Linda Durgan, from Carmarthenshire's Stop Smoking Service said that the number of enquiries had dropped off since the start of the ban.
"We had a lot of phone calls and people were very anxious on the day itself, but we have seen a gradual decline in that," she said.
Some businesses have said they have already noticed the effect of the ban, including Nigel Griffiths, who manages Llanelli's Argos bingo hall.
"We have lost about 11% of our turnover and about 3% of our customers at the moment," he said.
Alongside Wales, a smoking ban was also brought in for Northern Ireland in April 2007, while an English ban starts in July.
Scotland's ban has been in place since March 2006.
In Edinburgh only nine fixed penalty notices have been handed out. Only one of these involved a pub, for putting up its smoking shelter incorrectly.