The MTR says there will be no trains between Hung Hom and Mong Kok East stations on Sunday because of track works for the East Rail cross-harbour section.
Passengers are being advised to take the Tuen Ma Line or other lines.
A free shuttle bus service is operating between Hung Hom and Kowloon Tong but it will not stop at Mong Kok East.
The railway company said passengers should expect longer travelling times of between 10 and 20 minutes.