The closure is reported to be due to bus replacement services for Lewes and Brighton.
Mark Dunford got in touch to say it was chaos and that he was 'furious' as the closure 'nearly made us miss our train'.
He added: "Lots of cars are turning up and being turned away."
Amended services are running between Three Bridges and Brighton / Lewes this weekend and impacted routes on Southern are between London Victoria / Haywards Heath and Brighton / Ore / Littlehampton / Eastbourne / Bognor Regis / Hastings and on Thameslink between Bedford / London Bridge and Brighton.
This is resulted in bus replacement services for some services and others being cancelled, more information on that can be found HERE