Coutinho was expected to have his medical with Liverpool today before completing an £8.5 million transfer from Internazionale.
The 20-year-old will then apply for a work permit, which will not automatically be awarded as he has only played one game for Brazil.
Liverpool will be confident of securing a permit on appeal though and should now finalise the deal before the close of the transfer window on Thursday night.
Coutinho, who can play as a winger or a central playmaker, started his career with Vasco da Gama before signing for Inter for 4 millon euros in 2008.
He had to wait until his 18th birthday to join the club formally but then impressed in the first half of the 2010-11 season under former Liverpool boss Rafa Benitez.
Last season he joined Espanyol on loan and scored five goals in 16 appearances in La Liga.