The 25-year-old is due to fly out to Spain on Saturday evening to finalise the move with £105 million of the fee expected to be an up front payment, the remainder following in realistic add-ons.
Liverpool manager Juergen Klopp said the club could do nothing more to convince Philippe Coutinho to stay at Anfield after the Brazil playmaker sealed his dream move to Barcelona on Saturday.
"In the next hours we will inform you of the details of the player's arrival and presentation".
It's odd timing for the move as Coutinho can not play for Barcelona in the Champions League this season, having participated in the cup with Liverpool.
The transfer cost is only surpassed by the Paris Saint-Germain acquisition of Neymar last summer - and the impending permanent transfer of Kylian Mbappe at season's end.
Speculation surrounding Mahrez's City future has been rife this January transfer window and Liverpool are the latest club to be linked to the Algerian as they pick out possible Coutinho alternatives.
"Philippe was insistent with me, the owners and even his teammates this was a move he was desperate to make happen", Klopp said.
The player has a minor thigh injury and missed the club's past two games, including Friday's FA Cup third-round win against Everton.
While Coutinho will soon turn out for Barca in La Liga, he will not be able to represent them in the Champions League for the remainder of the season, having already played in the competition for Liverpool.
Coutinho's name briefly appeared on a Nike advert for Barcelona shirts last week before being removed.
With messages of peace Christmas celebrated across Kashmir
The head priests gave sermons on the life and teachings of Jesus Christ who gave world the message of peace, brotherhood and love. In an unpleasant incident, a church was vandalised on Christmas day by two unidentified drunken youths in Tura town of Meghalaya.