The Transport Department said some express rail trains between Hong Kong, Guangzhou South and Tianjin West have been cancelled due to bad weather.
The affected trains - G305, G306, G6505 and G6506 - were scheduled for Thursday and Friday.
The department said mainland authorities notified it about the cancellations, and it advised travellers to cross the border using the East Rail Line or other transportation.
Those who want to seek a refund, it said, can do so within 30 days on the express rail's official website, 12306.cn, or on the mobile app. It said people don't need to rush to West Kowloon Station in person to get the refund done.
The MTR Corporation, meanwhile, said it’s trying to learn more about the situation, and would provide more information as soon as possible.