Killen is out of contract at the end of the season

"I have given Chris a time limit because I have to get my squad together for next season," Collins told the Edinburgh Evening News.

"If he is not signing I have to find another striker."

The New Zealand international has scored 15 goals this season but has not played since 10 January after picking up an Achilles injury.

"I'm not putting any pressure on him but it is a fact of life I have to get my squad sorted out," added Collins.

"I have to put plans in place so I need to know if Chris will be staying.

"But that's the nature of football, players in the last year of their contract want to wait and see what their options are."

Meanwhile, Hibs have signed 16-year-old Austrian winger Elias Wagner.

Wagner is currently with Austrian Second Division club Admira Wacker Modling but has agreed a two-year deal at Easter Road.

"He plays wide right, he's very powerfully built for his age and quick," said Collins.

"Apparently there was a lot of interest in him but I think when people look in from the outside at our football club they realise that there's every chance players will get into our first team at a young age if they progress whereas at some of the bigger clubs you can get lost."