Four Singapore-based tour bus operators are no longer allowed to operate in Malaysia after they were found to have flouted licensing rules. The four firms had their licences cancelled after they were found offering express bus services and selling tickets online, the Malaysian Land Public Transport Agency (Apad) said in response to queries. Foreign bus operators are allowed to take tourists on overnight stays in Peninsular Malaysia, but cannot operate express bus services, nor sell tickets online, Apad added.   They must also submit the list of passenger names and the travel itinerary, which must start and end in Singapore, including destinations in Malaysia. The four firms, which were not named by Apad, were told about the cancellation of their licences on April 29 and May 2.   So far, 23 Singaporean bus operators have been granted approval to operate in Malaysia.   Malaysia issues express bus service permits only to companies registered in the country, reported Chinese-language daily Lianhe Zaobao on May 6. Cityline Travel and Luxury Coach - two of the four bus operators hit by the suspension - said in separate statements that the Singapore-registered buses they operate now cannot provide coach services to and from Malaysia because of regulatory constraints. Cityline Travel, in a Facebook post on May 7, said: "This suspension is the result of policy matters that are presently under review by the relevant authorities." Luxury Coach said it does not operate the same way conventional express bus providers do. The firm, which has an office in Orchard Plaza, said: "The nature of our tours, pricing structure, and added services differs significantly from Malaysian-registered express buses. "However, due to the flexibility we provide - especially with online return bookings - there has been a misunderstanding that we are competing directly with local express services targeting Malaysian commuters. "We are currently working with the relevant authorities to work things out and to position ourselves correctly by not breaching any laws." Cityline Travel, which has an office in Chinatown, said it is cancelling affected trips and processing refunds to customers, while Luxury Coach said it will transfer customers over to a partner company or give them a refund. Both firms said they are working with the regulatory bodies to resolve the issue, and have temporarily suspended coach services until further notice. The other two firms suspended are WTS Travel and Leo City Coach, the Zaobao report said. The Straits Times has contacted all four firms for comment. One affected passenger, Mr Chan Chee Sheun, had made plans to travel to Kuala Lumpur on May 28 with his parents to watch a football match at Bukit Jalil Stadium. But their plans have been thrown into disarray, as he had bought one-way tickets from Luxury Coach and Cityline Travel for the trip to Malaysia and back to Singapore respectively. The 29-year-old told ST he was not directly informed by the coach operators about the situation, and found out only after seeing their posts on Facebook. "It has caused a lot of inconvenience for my travel plans," said Mr Chan. The food delivery driver added that he had spent around $177 in total on the six tickets. He plans to buy tickets from other operators after he receives his refund from the two affected firms. Three Cityline Travel buses were stopped at a Malaysia checkpoint on May 4, when the buses were ferrying passengers back to Singapore, Zaobao said. A Straits Times check on WTS Travel's website found that the operator's booking system is under maintenance. It has several outlets in Singapore, including at Suntec City, AMK Hub, and Causeway Point. The affected bus operators have been providing coach services between Singapore and several destinations in Malaysia popular with Singaporeans, such as Resorts World Genting, Kuala Lumpur and Malacca.