THE immigration laws of Hong Kong must be brought in line with the Basic Law to allow a more lenient policy towards holders of second passports, a mainland official said yesterday. Chen Zuo'er, a Chinese representative on the Sino-British Joint Liaison Group, said a legal basis was necessary for future policy on returning emigrants. Mr Chen was speaking after a day of informal talks on immigration with the British representatives, headed by the Director of Immigration, Laurence Leung Ming-yin. He said the Immigration Ordinance and related laws should comply with Chapter Three of the mini-constitution, which outlined the rights and duties of residents in the Special Administrative Region. Mr Chen reiterated China's intention to adopt a lenient policy towards Hong Kong residents who hold a second passport. ''If Hong Kong emigrants are coming back, it means that they have a feeling towards Hong Kong and China. ''After all, many of those among that group are experienced professionals.'' Mr Leung said there was a need to allay the fears of Hong Kong people over permanent resident status and the issue of travel documents after 1997.