It said the destruction of water hydrants in the region, particularly in and around the central business district was affecting effective fire fighting.
The Service said this after the outbreak of another fire, which razed some wholesale shops in the Opera Square building, near Rawlings Park, in Accra on Monday.
Fire officers had a torrid time dousing the blaze.
The fire, which was believed to have started around 1600 hours, razed all wholesale shops on the top floor of the Opera Square.
However, the ground floor which harbours some retail shops, including banks such as the Bank of Africa and GT Bank, was not affected.
It took officers more than two hours to bring it under control.
More than 10 fire tankers from across fire stations in the city, including Makola, Ministries, Korle Bu and Abelenkpe were mobilised to fight the inferno.
As at 1940 hours when GNA reporters were leaving the scene, the blaze was yet to be quenched, with water from more than 10 tankers having already been exhausted.
Briefing the media on the disaster, Assistant Divisional Officer Grade Two (ADO2) Alex King Nartey, at the Public Relations Department of GNFS, Headquarters, said the absence of a ready water hydrants in and around the central business district, was posing a huge challenge to the Service during fire outbreaks.
He said most hydrants in the capital had been blocked by either through the dumping of waste materials or had had a building constructed on them.
As a result, officers were compelled to travel several miles to get access to water hydrants, leading to more damages during such disasters.
“Our hydrants are the easiest way to help us fight fires. In market like this, people build their shops on hydrants, people do illegal things and block these hydrants, so, we have hydrants but unfortunately sometimes the hydrants are not flowing.
“People have their shops on them, dumped rubbish in them so we are calling on people to desist from such habits so that when there is fire we can better serve them,” ADO2 said.
He urged the public to, therefore, protect hydrants to help minimise the level of destruction during such unfortunate incidents.
ADO2 Nartey also noted that firefighters had a tough time entering into the structure to fight the fire due to its complex security features.
He advised that Ghanaians prioritised their safety over security to reduce casualties during such disasters.
He assured that immediate investigations into the cause of the fire would be initiated.