The Hoops are keen to bolster their frontline before next Tuesday’s transfer deadline and have identified Giakoumakis as a target.
Ange Postecoglou’s side have already reached an agreement with VVV-Venlo over a €3m fee for the Greece international.
However, Celtic have not been able to get the deal over the line as they are yet to agree personal terms with Giakoumakis.
The 26-year-old is claimed to want €150,000-a-year more than the Glasgow giants have offered him.
With Celtic and Giakoumakis still not on the same page regarding the personal terms, they remain in negotiations over a deal.
The Bhoys will be hopeful of reaching an agreement with the Greek hitman soon and getting a deal for him over the line before the transfer window slams shut.
Celtic appear to have a free run at signing Giakoumakis, with Werder Bremen ending their pursuit of the centre-forward.
