A fault with the signalling system at Hilton Admiral means trains have to run at a reduced speed on the line towards Southampton.
Trains running between Bournemouth and Brockenhurst may be cancelled, revised or delayed by up to 20 minutes.
Disruption is expected until 12:00.
Check before you travel:
You can check your journey using the National Rail Enquiries real-time Journey Planner.
Compensation:
You may be entitled to compensation if you experience a delay in completing your journey today. Please keep your train ticket and make a note of your journey, as both will be required to support any claim.