They were called out to the area at 5 o'clock this morning.
Gardaí in Westmeath have issued 11 fines for breaches of covid-19 regulations.
The fixed notices were handed out after officers were called out to apartments in the Dublin Road area of Athlone at 5am this morning.
Gardaí had received reports of loud noises coming from the building.
Organisers of the gathering could be subject to a €500 penalty under latest restrictions while those attending will be subject to a €150 charge.