The firm has said it is ‘unable to commit’ to a re-opening date, despite Prime Minister Boris Johnson’s announcement on Monday that holiday parks can re-open from July 4.
Butlin’s has already said that its resorts in Skegness, Bognor Regis and Minehead will stay shut until July 16.
A spokesman said: “Following the Government announcement, we’re working hard to understand what this means for your holiday, which we know you‘re looking forward to.
“We’re still closed until July 16 and are unable to commit to a re-opening date. We hope that the Government will soon announce further measures that will enable us to open all our facilities and will update those of you with future bookings as soon as we can.
“We know this is a worrying time for many of you, and we’d like to remind you of our new guarantee which means you can re-schedule or request a full refund on your break.
“We just ask you to wait between 3 and 28 days prior to your arrival date before contacting us.
“For more details, please visit https://www.butlins.com/help-contact/coronavirus-guarantee
“We know it’s frustrating waiting to hear if your break is going ahead and continue to thank you for all of your support and patience during this time. We’re looking forward to welcoming you back as soon as possible.”
The three resorts have all been shut since March.