A report submitted to Liverpool City Council has recommended cutting the visiting supporters' capacity from 3,015 to 1,965 in an attempt to combat the problem of people blocking gangways.
The Ground Safety Advisory Group, who compiled the report after match between the two sides in April, suggest problems with United fans at Anfield are far greater than those of other visiting clubs.
"Pictures were presented which showed how the gangways at that game were affected compared to a similar high-profile game where persistent standing also occurred," said the report.
"The actions of the Manchester United supporters had overwhelmed the reasonable operations of the stewards through the management plan.
"This is an escalation of the actions of the supporters from previous games.
"It is not clear what more the club can reasonably do through stewarding measures to ensure spectators do not encroach in to gangways.
"Spectators from other away clubs attending the ground also persistently stand.
"However they do not spread out in to the gangways to the same extent that the Manchester United spectators do."
Liverpool City Council's licensing committee will make a final decision on the proposal at a meeting on August 8.