Lasogga spent last season on loan at Hamburg from fellow German side Hertha Berlin, scoring 17 goals in that spell and making him a permanent target for general manager Oliver Kreuzer.
However, Hamburg are about to receive a cash injection from investor Klaus-Michael Kuehne, who is threatening to change the management structure at Hamburg.
"As a private citizen and HSV fan, I can only say that I do not believe in this coach," Kuehne is quoted as saying by The Chronicle. "My personal opinion is the trainer must be replaced."
Newcastle are understood to be unwilling to up their wage offer after talks with the striker, and will wait to see how events at Hamburg unfold.