Liverpool forward Mohamed Salah's struggles in front of goal are down to the club no longer having the "well-drilled" front three that terrorised defences in the past, manager Juergen Klopp said.

Although Salah has scored 17 goals in all competitions at the halfway mark this season, he has scored only seven in the Premier League where he has averaged nearly 24 goals a season during his time with Liverpool.

The Egyptian forward has won three Golden Boots for most goals in a season, but has been far from his best after the summer departure of his strike partner Sadio Mane and injuries to Roberto Firmino, Diogo Jota and Luis Diaz.

"Of course Mo is suffering. It was a well-drilled machine the front three, everything was clear (in) what we were doing. Everybody suffers from that, that's clear," Klopp told reporters.

"It is specific, offensive play that requires a lot of work and lot of information, and not always obvious information. You create a feeling about a lot of these things, about where your team mate is and where to pass the ball without looking."

Mane moved to Bayern Munich in the close season while Jota, Firmino and Diaz have not played since the World Cup, with Liverpool falling to ninth in the standings.

Liverpool reinforced their attack with the mid-season signing of Dutch forward Cody Gakpo who is still adapting to the team, while Darwin Nunez has not been consistent, scoring just one goal in the FA Cup since the season restarted last month.

"In two or three weeks a couple more options will be available and we can mix it up. When Darwin is playing, he is obviously more high up, going in behind," Klopp added.

"We never played with a (number) nine before. Even when Sadio played in the position he was dropping (back) in moments. That's not Darwin's game, he wants to have balls at his feet and he's a real handful there.

"It is all good if they would all be in and we could build something, but we haven't been able to do that yet."