Celtic manager Ronny Deila admits it will be very difficult to complete his transfer business before the Champions League qualifiers.

Celtic begin their season in mid-July with the first of three potential qualifying rounds to reach the group stages.

The Norwegian will be far better prepared than he was this season, when Celtic were knocked out twice in the early months of his reign by both Legia Warsaw and, after a fortunate reprieve, Slovenian champions Maribor.

Deila also strengthened his squad in January by bringing in Gary Mackay-Steven and Stuart Armstrong from Dundee United, and has been firm in his stance that keeping key players for the push to make the lucrative group stages is more important than securing transfer income.

But to obtain transfer targets in time to bed in for the qualifiers could prove a step too far.

"That's what we want but I don't think it's going to happen," said Delia ahead of champions Celtic's final Scottish Premiership clash of the season, against Inverness on Sunday.

"There is a break after the last round of Champions League qualification. You have six days (until the end of the transfer window) and if we are in the Champions League then you can possibly do something.

"It's going on all the time and we want to get good players as quickly as possible, but everyone is saying the same thing, so it's a hard job.

"I'm hoping but I never expect things in football.

"It's a hard business and it's getting harder and harder, these transfer windows.

"It takes your energy as well but it's an important thing. I hope we have strengthened the team in June but I never expect anything."