Gardai and Revenue have launched a joint action to tackle the problem of suspected petrol stretching in Co Mayo.
The move is being made following concerns expressed by members of the public.
It will see Revenue continuing to sample suspect fuel while the Gardai say they will be stepping up their attempts to identify the perpetrators.
The two organisations will be sharing information and intelligence on suspected petrol stretching operations.
A joint statement from Revenue and An Garda Síochána warned consumers to take care with where they purchase their fuel.
“Both An Garda Síochána and Revenue are very aware of the risks posed to consumers’ vehicles, legitimate businesses and the Exchequer by all forms of fuel fraud. Motorists are advised to take care where they source their petrol and report any suspicions concerning adulterated fuel which may have damaged their engines. All such reports will be fully investigated,” the statement said.