The QPR striker was set to sign for the Reds this week, after a fee was agreed between the two clubs.
But despite flying out to Boston for his medical, where Brendan Rodgers’ side are currently based for pre-season, the deal may not now be finalised until the early part of next week, according to the Mirror.
The 27-year-old has agreed a four-year deal with Liverpool, despite interest from Arsenal and Tottenham.
It is unclear what the exact administrative issues are, but the move is still expected to go through as Rodgers continues to bolster his squad ahead of the coming campaign.
Southampton duo Rickie Lambert and Adam Lallana have already moved to Merseyside this summer, although the latter has been ruled out of the first three Premier League games of the new season with a knee injury.
Emre Can and Lazar Markovic have also joined the Reds’ ranks, while Southampton centre-back Dejan Lovren is also expected to move to Anfield over the weekend.
Written by Steve Milne