Ange Postecoglou hopes his first Celtic signing is imminent as he embraced the rebuilding job facing him.

The Australian has taken over a Celtic team which has seen skipper Scott Brown depart along with four loan players, while the future of out-of-contract Leigh Griffiths will be assessed.

The future of Odsonne Edouard, Kristoffer Ajer and Ryan Christie is also uncertain with all three entering the final stages of their contracts.

Postecoglou, whose first game will be at home to Danish side Midtjylland in the Champions League qualifiers on July 20, admitted he wanted his first signing as soon as possible.

"It's a challenging time all round the world in terms of signing players and the ability to even watch players these days is very difficult," he added.

"But the club is working awfully hard and I will push them as hard as I can and we are hoping we can make some announcements very, very soon.

"Certainly there's some emergency around at least a couple of positions, particularly with this game coming up in four weeks' time."

The former Australia and Yokohama head coach views the major rebuild as an opportunity to mould the team in his style of energetic, attacking football.

"Just about every job I have had has been an extensive rebuild," he added. "For a number of reasons. Usually you come in when people are needing change. Secondly, the way I get my teams to play is challenging, and requires a major shift, usually both in playing staff and the way we work.

"So it's not unusual. I guess the challenge we have this time is more time than anything else, given we are less than four weeks away from a very important Champions League game.

"That's probably the only bit that is a little bit different from the past, but in terms of the rebuild, this is the bit I enjoy.

"In terms of my management style, I am a builder. I like building teams that play a certain way and are exciting to watch, and that takes certain elements.

"It is difficult but this is the bit I enjoy, because this is the bit we put the bricks and mortar in place to build something special.

"Yes, we do have to make some changes, but at least I can make changes that will help us go in the direction I want to. Whether it's staff or footballers, I can bring in the ones I think will fit the picture.

"With the players we have existing, they will all be treated on merit, and the environment will be there for them to embrace, should they want to. And for ones coming in, we will bring ones that I know will fit."

The 55-year-old is well aware that second is nowhere in Glasgow but assured Celtic fans, who are still smarting from a barren season, that his outlook is the same.

He added: "I understand there is an immediacy and it's the world we live in nowadays, people don't want to wait long for too many things.

"But I have managed to navigate a career where I can merge the goals of building a football team and playing a certain way, with success at the same time. That's my goal here."

Postecoglou was speaking before reports emerged that Celtic had turned down £10million bids for Ajer from both Norwich and Bayer Leverkusen.

On the future of the Norway defender and Edouard, he said: "I haven't spoken to either of them yet. We will have discussions and make the best decision for the football club."