London Mayor Boris Johnson has said he is "not minded to provide additional funding" to prevent planned fire station closures and job cuts.
Last week members of London's Fire Authority voted against plans to close 10 stations and cut 550 firefighters' jobs, to save £28.8m over two years.
In a letter to Fire Commissioner Ron Dobson, Mr Johnson said he was "minded to direct" members over the cuts.
Members voted 9-8 against the plans but the mayor has the final say.
In the letter Mr Johnson said: "I am not minded to provide additional funding to the London Fire and Emergency Planning Authority (LFEPA) for 2014-15.
"I have set out my intentions as to the level of resources LFEPA should receive for 2014-15 not just on the basis of reductions in government grant but also on the basis of what level of frontline savings LFEPA can reasonably make without affecting public safety.
"Before deciding whether or not to direct, and what the terms of that direction might be if a direction were to be issued, I would welcome LFEPA Members' views on my proposed course of action."
The LFEPA met earlier on Wednesday to discuss its response to Mr Johnson's letter.
London Assembly Member and Labour fire spokesperson, Fiona Twycross, said: "Boris is cutting too far and all to fund his penny a day council tax cut. The mayor has asked if we want him to legally direct us to make these cuts, and our answer is a simple one - 'No'.
"If he is serious about ensuring the safety of Londoners he needs to put his money where his mouth is and provide adequate funding."
Members have asked the LFEPA to set up a working party to identify any further savings in order to protect the frontline, she added.