A 29-year-old man has been charged with raping a woman and then committing a string of attempted armed robberies within an hour across Melbourne's inner-north on Thursday.

Abdirizak Hashi, from Fitzroy, allegedly assaulted a woman in Drummond Street, Carlton, about 11.30am.

The victim was reportedly a 15-year-old girl.

He then allegedly held-up a Caltex service station on High Street, Northcote, armed with a makeshift flame-thrower about 12.10pm.

CCTV footage broadcast by Channel 7 shows a man at the service station using an aerosol can and a cigarette lighter to threaten the woman behind the counter.