Nearly 4,300 households and businesses in Dublin have sought help in dealing with rodents since January.
The problem has been brought on by "breakouts by rats from sewers" as the Covid- 19 pandemic cut back the work of pest-control teams.
Figures provided by the HSE show pest-control officers have visited an average of 70 premises each day in Dublin so far this year in relation to rodent infestations.
A total of 4,292 calls for help were received between January and August and resulted in nearly 17,200 visits to properties by HSE staff.
Unlike in previous years when the majority of reports of rodent infestations were on the city's northside, they are effectively split down the middle this year, with 2,155 reports from homes and businesses on the northside and 2,137 from the southside.
The latest figures suggest 2020 is on target to exceed the 22,607 visits recorded by pest-control officials last year.
Official figures indicate pest control officers carry out an average of four visits to each location where rodents are reported.
Dublin City Council admitted in June that there had been a big increase in the number of rats leaving the sewers to roam city streets and suburbs as the activities of pest-control teams were curtailed by Covid restrictions.
Former Sinn Féin councillor Críona Ní Dhálaigh described during the summer how rats spotted in the Oliver Bond flats were "big enough to put a saddle on".
South Dublin County Council said it had received an increase in rodent complaints between March and June, which largely related to domestic back gardens, parks and roadways.
A council spokesperson said the problem had been exacerbated by the lockdown.
"One factor is that people were mostly housebound from March until June and spent more time in their gardens and public parks and witnessed more rodent activity," the spokesperson said.
Local authorities in Dublin also claim the closure of most food outlets and pubs and the resulting reduction in both solid and liquid waste going into sewers and waste bins forced rodents out into more public places.
"Most rodent activity can be traced back to breakouts by rats from sewers," the spokesperson said.
The council said persistent poisoning was a crucial factor in controlling the rat population underground.