Reported instrument creating fires (5)
I believe the answer is:
sacks
'fires' is the definition.
(I know this)
'reported instrument' is the wordplay.
'reported' shows a homophone (sound like).
'instrument' becomes 'sax' (sax is a kind of instrument).
'sax' is a homophone of 'SACKS'.
'creating' acts as a link.
(Other definitions for sacks that I've seen before include "Gets rid of" , "Plunders; bags" , "Terminates employment as punishment" , "Bags; wines" , "Raids; boots out" .)