Gardai believe a number of the gorse fires that hit dozens of areas across the country this week were started deliberately.
Fire crews have been forced to battle large infernos in counties Wicklow, Wexford, Clare, Mayo, Galway and Sligo over the past number of days.
Farmers have been urged to stop burning vegetation as a traditional prelude to turf cutting.
A massive blaze hit the Little Sugar Loaf Mountain in Co Wicklow on Wednesday. It was only extinguished in the early hours of yesterday and the cause has not been established.
After fire crews had dealt with that incident, another fire broke out at Tara Hill, in Gorey, Co Wexford. Three units were still battling that blaze last night.
In Co Tipperary, fire crews were battling last night to contain a fire that broke out on the Silvermines Mountain, just south of Nenagh.
The sizeable blaze broke out yesterday evening and was visible to motorists on the M7.
Units from across Tipperary and Limerick were dispatched to deal with the inferno. At one point on Wednesday, not a single firefighter from Co Clare's seven fire stations was available to respond to a call because they were tied up.
Crews from four stations spent almost 10 hours battling gorse and forestry blazes close to homes on Mount Callan in the west of the county.
Gardai and Coillte believe that almost all of the fires which have broken out following the prolonged sunny, dry spell in the western counties were set deliberately.
Fire crews from Ennis and Kilrush were last night battling to control several fires which are believed to have been started maliciously in Kilmaley.
In west Connemara, gorse fires threatened homes and caused two oil tanks to explode.
Major outbreaks occurred in a number of areas in Co Galway including Recess, Oughterard and Moycullen. In Clifden, a total of four fire tenders battled a blaze until 6am yesterday.
Coillte has a helicopter based in Galway on constant standby as workers at the forestry agency remain on high alert.
A spate of fires also raged across Co Mayo.
The Irish Farmers' Association has rushed to distance its members from responsibility for the fires, pointing to the damage inevitably caused to farm property from the outbreaks.
Regional development officer Roy O'Brien said: "The problem with gorse fires is that they are deliberately set on fire and that's what causes the problem. Farmers are the last people who would want to do that."