United will play the final game of their five-match pre-season tour of Australia and the Far East in the venue on Monday amidst fears over the playing surface.
Premier League chief executive Richard Scudamore told Sky Sports News that player safety had not been compromised after Tottenham defender Jan Vertonghen suffered an ankle ligament injury on the sodden surface in their game against Sunderland.
United face local team Kitchee FC in Hong Kong and Moyes admits he is approaching the match with some trepidation, with heavy rain expected to fall until the day of the game.
"I do have concerns about the surface," he said.
"It is mainly due to the weather. That is an act of God. We can't do anything about that.
"But we will travel to Hong Kong and hope the conditions improve and the pitch is in a better state than it has been in recently."
United drew 2-2 with Cerezo Osaka on Friday and afterwards Moyes confirmed that Shinji Kagawa, who scored the opening goal against his former club, would not feature against Kitchee.
Kagawa is still owed some time off after playing for Japan in the Confederations Cup in Brazil, with the midfielder breaking into his holiday to play in his homeland.
"We have given him more holiday because of his football with Japan in the summer," added Moyes.
"We try to give all the players four weeks' holiday if possible.
"He hasn't quite had that time so we will give him another week's rest, although he will do some more training with the club here, so he can have that time at home in Japan."