The former Manchester City midfielder moved to St James' Park during the January transfer window after a £8million summer transfer to Aston Villa turned sour.
He has been told by Villa boss Gerard Houllier that he has no future at the Midlands club and so has set his sights on securing a permanent move to the North-East.
However, a succession of injuries have prevented Ireland from making his Toon debut, though he is set to be named in the squad for the clash with Manchester United on Tuesday.
And boss Pardew has challenged Ireland to prove his worth in the final few games of the season or the club will send him back to Villa.
Pardew told the Northern Echo: "I don't think there's pressure on Stephen as a player because he's already proven he is a very good player at Manchester City.
"The question with Stephen is whether he can do it in a black and white shirt. We've got this period between now and the end of the season where he has to show he can. If we don't see it in the next six games, it's highly unlikely we are going to bring him here permanently."