The Bafana Bafana defender was expected to fly to London this week to finally link up with the Tottenham Hotspur squad, but the cold snap in the UK has meant he has yet to receive all the required paperwork.
The 23-year-old will definitely not feature in the club's next two league matches against Fulham and Everton but his agent Glyn Binkin is confident he will be in contention for the FA Cup match against Charlton on January 9.
"There's been a slight delay because of all the snow - all the documents we had to send over were caught up in the post as a result and things have taken slightly longer than we had anticipated," he told Football365.co.za.
"As you know, the work permit was granted a few weeks ago but we are just waiting for the final visa to be validated. I'm certain he'll travel before the end of next week."
Spurs have enjoyed a successful Christmas so far, picking up two victories despite being reduced to 10 men in both games.
But with injuries to defenders William Gallas, Ledley King and Jonathan Woodgate, manager Harry Redknapp had planned to give his new signing a first taste of action this week.
That will have to wait for now, but Binkin believes Khumalo will get his chance soon enough.
He said: "They've had a lot of injuries and suspensions so it's going to be a great opportunity when he finally gets there. I hope he will rise to the occasion."