The firemen say some of them have not even been trained in basic skills like knowing how to swim.
Sharad Kuveskar, working president of the Mumbai Firefighters Services Union, said that two years ago, former additional municipal commissioner Manisha Mhaiskar had promised that lifeguards will be recruited for all the city's beaches.
"However, no lifeguard was recruited and the firemen have to do this job too with limited skills. For that, the BMC does not even provide us any extra benefits," he said.
The union had sought a meeting with civic chief Sitaram Kunte about 10 days ago, but has not received any response so far.
The BMC has deputed 45 lifeguards on seven beaches along with 63 firemen.
The fire brigade department had appointed 60 firemen to be part of flood rescue team (FRT), which was formed after the 2005 deluge.
A senior fire officer said that lifeguards would be recruited soon. "The recruitment of lifeguards is in process. The administration is also considering providing firemen additional benefits for the extra work carried out by them beyond their call of their duty," he added.