Investigations are taking place in Farnham Road (credit: Simon Ford)
A spokesperson for the Metropolitan Police said officers were called to reports of a fight in Dudley Road, Harold Hill, just before 5am today.
No suspects or victims were located there.
Later on this morning, a man was found in James Watt Way, Erith, suffering from stab wounds and a head injury.
Police believe he is the victim of the altercation which began in Harold Hill, although it is not clear where he was stabbed.
The man, who is in his 30s, has been taken to a south London hospital but it is not yet known how serious his injuries are.
No arrests have been made.
Anyone with information is asked to call police on 101 quoting CAD 839/02DEC or Crimestoppers anonymously on 0800 555 111.