Latest figures from Suffolk Fire and Rescue Service show falling response times and fewer on-call firefighters.
The figures were presented to a meeting of the cross-party Suffolk Fire and Rescue steering group this week.
With the year’s final quarter figures still to be calculated, response times for the bulk of last year showed a worrying trend.
The number of fire crews arriving at a property fire within 11 minutes had dropped from 73.1 per cent in 2015 to 71.87 per cent in 2016.
Targets for a second crew arriving within 16 minutes, and those attending road traffic collisions within 13 minutes, had also dropped.
The availability of on-call firefighters was down on 2015, with the county-wide average falling by almost one per cent.
Suffolk County Council’s Labour Group fought against plans to replace Sudbury’s second fire engine with a rapid response vehicle and opposed full-time crews being removed in Bury St Edmunds and Ipswich.
The group’s spokesman for public protection, Peter Gardiner, said: “Coverage and safety are only getting worse. With so much accommodation above commercial premises in Sudbury, this is a serious concern for the town.
“Labour is pledging to fund a full-time day crew in Sudbury if they are leading the county council after May.
“This would increase coverage for the town and the surrounding area and enable the fire inspections that are so important in preventing emergencies from occurring.”
Suffolk Fire Brigades Union secretary Roy Humphreys added: “Bringing back full-time firefighters would solve the recruitment problem for part-time firefighters in Sudbury.
“We have been advertising for on-call firefighters for over a year and still have a number of vacancies, particularly during office hours.”
Matthew Hicks, county council cabinet member for public protection, said: “The Conservative administration has, over recent years, done everything possible to protect it against reductions in grant funding from the Government.”
He said there had been investment in fire stations, training facilities, fire engines, clothing and equipment, highlighting the operational launch of a new fleet of engines in Bury St Edmunds,
“Suffolk Fire and Rescue Service monitors and reports on its performance regularly,” added Mr Hicks.
“We continue to work hard to recruit on-call firefighters and will continue to introduce measures and more flexibility to improve the availability of on-call stations across the county.”