Fifteen of these extra permits will go to the children of Hong Kong residents and 10 to mothers.

Assistant Secretary for Security Ingrid Ho Poi-yan said part of the extra quota would go to mothers and children of split families.

Miss Ho said the extra permits would also be given specifically to children born to Hong Kong residents.

''It would not be in Hong Kong's best interests to have a sudden influx of people on July 1, 1997 who would automatically have a right of abode here under the Basic Law,'' she said.

''Our best estimate for the number of potential Hong Kong residents [now living in China] is 70,000 to 100,000, but we're really not sure.'' She said the Government would assess the social and economic impact of raising the quota before deciding, in six months to a year, whether to raise the level again.

''The Chinese authorities have to consider our proposals and have to do something to make sure it is really the people who have families in Hong Kong that would be allowed to come here.'' Mr Asprey said: ''What we are seeking to do is find some means of smoothing into Hong Kong annually people who after 1997 will have the right of abode.'' Many relatives of Hong Kong residents not prepared to wait for their permits have been entering the territory illegally. Some who come with two-way permits overstay their visa.

Immigration officers yesterday arrested 12 people for overstaying. They will be repatriated to China.