The Brazil international is ready to put pen to paper on a contract which will make him the Reds' highest earner.
His current deal runs until 2020 but the new contract, which club officials hope will be wrapped up in the next 48 hours, will keep him at the club until 2022.
Philippe Coutinho is close to agreeing a new five-year deal with Liverpool
Despite the interest his improved performances have attracted around Europe and particularly from the Catalan giants, there is set to be no buyout clause inserted in the contract.
Both Liverpool and the players' representatives are understood to believe it would do little stop a move going ahead if the player wanted to leave in the future.
However agreement on his new contract – which is believed to have nearly doubled his £75,000 a week wages – confirms the Brazil forward is happy at the club and on Merseyside which he has said "feels like home".
Coutinho will become Liverpool's highest earner
Jurgen Klopp will be pleased to tie Coutinho down to the club
And that he continues to believe that the Premier League is well suited to showcase his considerable talents.
Coutinho, 24, has proved a massive hit at Anfield since signing from Inter Milan for £8.5million in January, 2013 and has blossomed under Jurgen Klopp.
Since his move he has scored 34 goals in 163 appearances and Coutinho has six this season despite missing six weeks with ankle ligament damage from November to January.