Grewcock, a second-half replacement in the Lions' 21-3 defeat, was cited by South African independent citing commissioner Willem Venter for an alleged incident in the 63rd minute of the match.
He will appear before a judicial hearing at 11.30pm British time at the Canterbury Rugby Football Union offices.
Grewcock, who had only just entered the fray in place of Ben Kay when the alleged incident took place, has a chequered history of playing in New Zealand.
The 32-year-old was sent off playing for England against the All Blacks on the 1998 'Tour of Hell' and was cited for stamping during the second Test on last year's similarly disappointing trip.
Added to that, Grewcock missed England's successful 2003 tour, when Sir Clive Woodward's men beat the All Blacks in Wellington, because he was serving a suspension for punching Lawrence Dallaglio.
Grewcock knew his temperament would be tested during the tour but when asked before the Lions' departure whether that is one area of his game that has improved he replied: "Definitely."
The Bath lock continued: "I want to go out there, I want to play as many games as possible and, same as the rest of the guys, try and play in the New Zealand Tests.
"The opposition's opinion? Whatever they think is up to them. I am there to concentrate on my job, do as well as I can for the team.
"The key thing is that the last games (when he was sent off in 1998 and cited in 2004) we lost. It is unfortunate that that is the way it went.
"Obviously this time round I would much rather go and not be sent off and win the game. That would be ideal."