Their eight day strike is due to end at the weekend, but firefighters will walk out again on Monday evening for another eight days.
The army's green goddess crews, who have been covering for the 1,400 striking firefighters since Friday morning, have been struggling to cope with a large number of hoax calls. Over the weekend, there were 1,020 calls but the vehicles attended only 300 incidents.
The most serious incident was a scrapyard fire in north Merseyside in which hundreds of people were evacuated from their homes on Sunday night. Four green goddesses - escorted by police officers - were called to the fire. Most of the crew were RAF personnel.
The Fire Brigades Union claims that the figures showed the army was not coping and the public was being deprived of proper cover.
The dispute has been caused by plans to promote non-uniformed staff to management positions.
It is estimated that it will cost around £1m to provide cover during the first strike.
Malcolm Saunders, Merseyside's chief fire officer, said the firefighters were grossly irresponsible to organise a second strike. "I am extremely disappointed," he said.
He said the military had provided excellent cover. "Everything has been running very smoothly," he added.
"They have been protecting the public of Merseyside very well."
Les Skarratts, the Merseyside Fire Brigades Union's secretary, said that the second wave of industrial action had been bornout of anger and frustration that the fire authority had not moved one inch towards meeting their demands.
