Saoud Al-Mohannadi chaired the organising committee for the competition, which starts on Saturday, and is vice president of the Asian Football Confederation (AFC).
A Qatari official told Reuters that Mohannadi was on Thursday stopped from boarding an Oman Air flight to Abu Dhabi from Muscat. He was told by the airline that his name was not on a list held at Abu Dhabi airport, another source said.
An AFC spokesman said Mohannadi had arrived in Abu Dhabi on Friday. It was not immediately clear which route he had taken.
Other than in special circumstances, Qataris have been prevented from entering United Arab Emirates, Saudi Arabia, Bahrain and Egypt since the four countries launched a diplomatic and trade boycott of Qatar in June 2017.
They accuse Qatar of supporting terrorism, a charge that Doha denies.
Qatar will host the 2022 World Cup, which football's global governing body FIFA hopes to expand to 48 teams from 32, suggesting the country could share hosting duties with neighbouring Gulf states.
Qatar has said it will only decide on any expansion of the World Cup after seeing a FIFA feasibility study expected by March.
The AFC is one of six continental football confederations that make up FIFA.
The Asian Cup is held every four years and the 2019 edition runs until Feb. 1.
(Reporting by Eric Knecht; editing by John Stonestreet)
