Lastminute.com has been warned by the industry watchdog after it emerged a deal it had advertised wasn't actually available.

The website was accused of "misleading" pricing after a woman complained that she was asked to pay an extra £70.77 on a £568 hotel and flight package to New York last September on the grounds that the price was no longer available.

The Advertising Standards Authority (ASA) said consumers would have understood the ad to mean that £569 was the total price they would pay for the flight and hotel package, notwithstanding the cost of any optional extras.

Lastminute.com said it always offered customers the option not to proceed with the booking if it was no longer suitable for them.

It added that the products it offered were "dynamic" as it relied on a global distribution system for information on up-to-date airline and hotel availability, which could change at any time during the booking process.

The ASA said: "Approximately an hour after making a booking request for the package at the quoted price, which included making the payment, the complainant was informed that the price had increased and they would need to pay an additional sum of £70.77 in order to maintain the booking.

"Because the package was not available at the price quoted in the ad, we concluded that the price statement was misleading."

The ASA told lastminute.com "to ensure that they could demonstrate that holiday packages were available at the prices for which they were advertised at the time they were seen by consumers".