Moyes is reportedly planning a £150m overhaul of United's squad as he looks to build on a difficult first year at Old Trafford, but is concerned that the World Cup could hinder his plans.
"It's difficult as players are going to be going away for the World Cup so it's maybe not quite as easy as, ideally, all clubs would like to get the work done early," he said.
"We cannot guarantee it but we will try to make that happen. I've got to say I'm well into my planning with my thoughts and ideas, getting ready for next year."
Moyes has also warned the club's fans to be wary of red herrings among the many names linked with moves to United.
"Not everything you read is correct, I've got to say that," the manager continued.
"We're linked with player after player and every time I go to a game I'm supposed to be signing three or four players from that game.
"That isn't the case but everyone is well aware we are looking to make signings and will try to do that whenever the opportunity arises. It will probably be after the end of the season before anything takes place but we have got to look to do one or two things."
Meanwhile, Moyes is hoping for good news on Robin van Persie's knee injury as the Dutch striker steps up his recovery programme in the Netherlands.
"Our medical team is heading out there to see him this week and get a better feel as to exactly where he is," he said.