Lawyers for Mr Adams asked two judges to declare that the exclusion order, made last October under the Prevention of Terrorism Act, breached European and domestic law. The Home Secretary refused to revoke the order in January.
Robin Allen, for Mr Adams, said the ban coincided with an invitation to the Sinn Fein leader from Tony Benn, the Labour MP, to visit Parliament. It was at a time when he might have disclosed the existence of secret talks between Sinn Fein and the Government.
The hearing continues today.