It has been reported that internet death threats had been made against the Norwegian official and that he had been "smuggled out of the country" under police escort and advised to change hotels.
"Following media reports claiming threats have been made against the referee of last night's game, Chelsea Football Club would like to make clear that it condemns any form of threat against players, officials or supporters," the club said in a statement.
"If provided with proper evidence Chelsea will take the strongest action against any season ticket holders or members who have participated in this activity.
"Everybody connected with Chelsea is very disappointed with the events of last night. However we would stress that we have received no evidence that Chelsea fans are involved in any of the alleged threats reported."
"As a result of these reports we have also been in contact with the police who likewise had not received any complaints."
Chelsea fans were upset Ovrebo did not award them a penalty, despite several strong appeals, during the 1-1 draw at Stamford Bridge that sent Barcelona into the final on the away goals rule.
Several players, notably striker Didier Drogba, remonstrated furiously with the referee after the tie, which was settled by Andres Iniesta's stoppage-time goal.
Swedish referee Anders Frisk retired after he and his family received death threats following his dismissal of Drogba against the same opponents in the 2005 Champions League.
Ovrebo told Aftenposten that he had been informed by UEFA not to make any comment on the furore.
"Because of the circumstances after the match, Uefa has asked me not to comment to the press," Ovrebo said.
Former international referee Graham Poll commented: "This morning he's being smuggled out of our country under police escort - this is a referee of a football match. That is a disgrace.
"When he booked in a hotel they had to change the hotel he was staying at because of the fear that maybe fans would find him."