ONLY ethnic Chinese or naturalised citizens will be able to apply for loans under regulations limiting the scope of the Government's sandwich class housing scheme. Adjustments to the scheme will also mean residents will have to declare any overseas properties they own when they apply for a loan of up to $500,000 from the Government to buy a new home. Eighteen applications have been received since the scheme was launched last Friday. The Housing Society, which administers the $2 billion scheme to help sandwich class families buy flats, said yesterday it was ''fine-tuning'' procedures to clear up misunderstandings. The criteria states that the applicant must be a permanent resident of Hong Kong or entitled to a Hong Kong British passport. It means that either the applicant must be an ethnic Chinese living here for more than seven years or, if not Chinese, he must have been naturalised in Hong Kong. But some non-ethnic Chinese minorities last night said the criteria discriminated against them. At the same time, legislators accused the society of a lack of adequate planning. The local Indian community described the changes as a rule ''preventing taxpayers from enjoying benefits from the Government''. The secretary-general of the Council of Hong Kong Indian Associations, Krishan Rathi, said: ''Like all Hong Kong citizens, we pay taxes to the Government each year. Many of us were born in Hong Kong or have been living here for decades. ''The scheme is supposed to be based on monthly incomes. I cannot understand why we should be rejected from the scheme.'' Legislator Lee Wing-tat said the hasty change demonstrated that the society had not thought through the scheme before launching it. ''It is incredible that they change the rules of the game when the game has already started,'' said Mr Lee. He said he would summon society officials to report to the Legislative Council's housing panel after the first phase of the scheme had finished. Colleague Albert Chan Wai-yip demanded that the criteria be removed, saying it was unfair to non-ethnic Chinese minorities. The society's estate management director, Wong Lai-chun, said: ''There is no change to the criteria. We supposed they [were] understood and thus we did not put them on the application forms at the very beginning. ''The amendment to the form is only to clarify the points and make the scheme clearer. We shall certainly be in a better position to assess whether the criteria need to be adjusted after this phase's experience.'' Miss Wong said she did not know how many of the application forms received so far would be invalid because of the criteria. She added they might be considered case-by-case. The rules also ask applicants to disclose overseas property ownership. The society said that was to ensure a more accurate assessment and it assured that no applicant was disqualified only because he owned properties overseas. The society has received 4,022 inquiries since it announced the scheme last Friday. Most callers wanted clarification of the eligibility criteria.