After-hours drinkers in some pubs in the west of Ireland may be combining their alcohol with a second illicit pleasure - a few puffs of cigarette smoke.
Due to a number of complaints, environmental health officers suspect that the practice is becoming more widespread.
"We have reason to suspect that a number of publicans may be allowing customers smoke after closing time when access isn't available to the premises any longer," Mr Cathal Kearney, principal environmental health officer for Mayo, said yesterday.
"We will be investigating all complaints of this nature and informing the gardaí in relation to breaches of licensing laws."
There was increasing evidence that some publicans believed after-hours was a safe time in which to light up, he added.
"Contrary to what some publicans might believe, we do have powers of entry after-hours and we will implement them.
"If we get complaints of this nature we will be asking gardaí to accompany us to the premises where the suspected offence is taking place, if necessary."
Mr Kearney confirmed that after-hours inspections are planned, particularly for one small Co Mayo village with a number of public houses where smoking and after-hours drinking had been reported from a number of sources.
The latest figures issued by the Western Health Board in relation to the smoking ban show that 2,926 inspections were carried out in the board region of Galway, Mayo and Roscommon between the start of the ban and the end of June.
Galway (1,479) topped the list for inspections, followed by Mayo with 1,032 and Roscommon with 425. There were a total of 137 complaints - 87 in Galway city and county, 35 in Mayo and 15 in Roscommon.