Ticketmaster may have breached consumer laws by failing to warn Oasis fans that the price of tickets might soar while they were queueing, experts have said, as it emerged that the company plans to apply “dynamic pricing” more widely.

Excitement about the Mancunian band’s long-awaited reunion tour descended into dismay and outrage over the weekend after fans complained that tickets for 17 shows in 2025, expected to make millions for the Gallagher brothers, were hiked up without warning.

Dynamic pricing, which is common in the US but relatively unusual in the UK and Ireland, meant that some fans queued all day long only to find that £135 standing tickets had risen to £355 when the time came to confirm their purchase.

Fans said they were left with a choice of missing out or paying more than they felt able to, and that they only had minutes to decide.

The government announced on Sunday night that it would include dynamic pricing in a review of ticketing that was due to focus on Labour’s plans to ban “rip-off” resale sites and ticket touting.

But on Monday, consumer law experts said that while dynamic pricing was not illegal, the way Ticketmaster applied it may have breached consumer regulations if it was not clear to fans that the price of basic standing tickets might increase.

Sylvia Rook, the lead officer for fair trading at the Chartered Trading Standards Institute (CTSI), said: “Dynamic, or fluid pricing, is not specifically prohibited by consumer protection law; the important factor is that consumers are not misled by the indicated price.

“It is a breach of the Consumer Protection from Unfair Trading Regulations (2008) if a trader misleads consumers regarding the price of goods and services, if that causes the average consumer to take a different ‘transactional decision’.

“In this case many consumers would not have joined the queue had they known that the price would have increased by the time they were able to purchase, and many fans could not afford the increased price.”

The Guardian approached Ticketmaster on Sunday to ask if consumers had been warned about the dynamic pricing model and whether the Oasis sale complied with consumer regulations. The company has yet to respond.

On Monday, the consumer group Which? called on the competition watchdog, the Competition and Markets Authority (CMA), to clarify whether Ticketmaster’s use of dynamic pricing for the Oasis tour was “legal under current rules”.

Which? said: “In the meantime, it’s essential that companies are transparent about how they will use dynamic pricing, so that consumers don’t get a nasty shock at checkout.”

Ticketmaster has said that the final decision on pricing strategy rested with Oasis and the band’s management. They have yet to comment.

The Advertising Standards Authority said on Monday that it had been flooded with more than 450 complaints about “misleading claims about availability and pricing”.

Despite the backlash, comments by the chief executive of Live Nation Entertainment, which owns Ticketmaster, indicated that fans in the UK, Ireland and Europe can expect dynamic pricing to become much more common.

Speaking in February, as Live Nation unveiled a 36% increase in annual revenues to $22.7bn, its chief executive, Michael Rapino, said: “Outside of the US, we’re in the first inning … We’re just rolling this [dynamic pricing] out around the world. So that’s the great growth opportunity, obviously.

“We’ve had it in Europe but [it’s] still in [its] infancy stages.”

Oasis fans who spoke to the Guardian said they had not seen any warning that the original advertised price might rise by nearly threefold.

Jack Simpson, 44, from Leeds, said: “We were there [queueing] for hours and only one out of 15 got through and got four tickets. Everyone else was getting told the only tickets left were £350. It was a bit disgusting.

“The whole thing feels a bit grubby. So many people felt joyous [about the reunion] after years of not much positivity. People were really upbeat and this has marred it at all.”

Simpson, who owns a music venue called Hyde Park Book Club, was one of at least seven fans who told the Guardian that they had not seen any warning during the ticket-buying process that prices might surge by the time they came to confirm their purchase.

In Ireland, the tánaiste, or deputy prime minister, Mícheál Martin, described the pricing row as “quite shocking” and said there may be a case for the country’s consumer body to look into dynamic pricing.

Mary Lou McDonald, the president of Sinn Féin, said working-class Oasis fans were being “thrown under the bus” over the pricing system.

The Guardian has approached Ticketmaster for comment.