A £5,000 fine for anyone in England trying to travel abroad without good reason is due to come into force next week as part of new coronavirus laws.
The penalty is included in legislation that will be voted on by MPs on Thursday.
Foreign holidays are currently not allowed under the “stay at home” rule which ends on Monday.
Prime Minister Boris Johnson said it was “too early” to set out new foreign travel rules for the summer.
Mr Johnson told a Downing Street news conference he hoped for more information by 5 April.
He said: “A lot of people do want to know about what’s going to happen on the holiday front and I know there’s a great deal of curiosity and interest.”
From next week the ban on leaving the UK will become a specific law, backed up by the threat of a fine.