Seplat now has until 5pm on 13 February to decide whether it'll firm up an informal offer originally made in December.
City analysts had voiced doubts over an offer coming to fruition, with broker Oriel saying in a note to clients that "another extension, in light of the new situation", was the most likely outcome.
More on this story: Timeline - what went wrong for Afren?
Afren has suffered amid looming debt repayments, and global oil prices which have slumped 60 per cent since July last year.
The London-listed company revealed it required a $200m (£133m) cash injection to avoid running out of funds on Tuesday, sending its shares down as much as 72 per cent.
It is in talks to defer a $50m payment due at the end of next month, and is considering whether to use a 30-day grace period for its $15m interest payment, due 1 February.
Afren's share price closed up 26 per cent at five pence this afternoon.