CANTO-POP came to the Great Hall of the People last night as some of Hongkong's best known singers performed on the stage usually reserved for the likes of premier Mr Li Peng and President Mr Jiang Zemin. Instead of the long rows of seats seen during the National People's Congress last month, the stage was bedecked with huge red lanterns, white satin drapes, coloured lights and dry ice. Below in the auditorium, National People's Congress deputies were replaced by 3,000 young fans, although Mr Lu Ping and Mr Rong Yiren were also there. The 21/2-hour concert was not a particularly raucous affair. Most of the fans stayed in their seats and the closest anyone got to dancing was a gentle swaying in the back rows. The only hint of controversy came from singer Andy Lau, much to his own embarrassment but the evident delight of the audience. During an interview on stage, Lau said: ''I'm happy to be here in Taipei.'' That probably got him the biggest cheer of the night. Most of the audience were specially invited or received tickets from their work units. Some tickets did change hands for about 250 yuan (HK$337) each, or about the average monthly wage for a factory worker in Beijing. Security on the door was so tight that holding a valid ticket was no guarantee of entry. Foreigners, for example, were not allowed into the hall. ''There are no foreign guests allowed in this evening,'' one of the dark suited security men explained to two middle-aged Europeans brandishing their tickets. Only after being told the tickets were part of the allocation given to TVB did the usually unflappable security men relent and allow the Europeans in. Once through the doorway, guests had to have their hand luggage pass through an X-ray scanner and then walk through a metal detector, before finally being admitted.