Rule 31 of Non-Contentious Probate Rules state that :
Where a person to whom a grant would otherwise be made is under the age of 21 years, administration for his use and benefit until he attains that age shall be granted :
(a)    to the parents of the person jointly or to any guardian appointed by the court; or
(b)   if there is no such guardian able and willing to act and the person has attained the age of 16 years, to any next of kin nominated by the person or, where the person is a married woman, to any such next of kin or to her husband if nominated by her.
Also, administration for the use and benefit of the person under the age of 21 years until he attains that age may be granted to any person assigned as guardian by order of the Registrar in default of, or jointly with, or to the exclusion of, any such person as is mentioned in above paragraph; and such an order may be made on application by the intended guardian, who shall file an affidavit in support of the application and, if required by the Registrar, an affidavit of fitness sworn by a responsible person.
Where a person under the age of 21 years who is sole executor has no interest in the residuary estate of the deceased, administration for the use and benefit of the person until he attains the age of 21 years shall, unless the Registrar otherwise directs, be granted to the person entitled to the residuary estate.
Where by virtue of section 25 of the Probate And Administration Ordinance, a grant is required to be made to not less than 2 administrators and there is only one person competent and willing to take a grant under the foregoing provisions of this rule, administration may, unless the Registrar otherwise directs, be granted to such person jointly with any other person nominated by him as a fit and proper person to take the grant.

Rule 29 of Non-Contentious Probate Rule states that :
Where the deceased died domiciled outside Hong Kong, the Registrar may order that a grant do issue :
(a)    to the person entrusted with the administration of the estate by the court having jurisdiction at the place where the deceased died domiciled ;
The rule under r.29(a) is invoked when an applicant has already obtained a grant in the court of the place where a deceased died domiciled, but resealing of that foreign grant is not permissible.
(b)   to the person entitled to administer the estate by the law of the place where the deceased died domiciled ;
The rule under r.29(b) is invoked when a deceased died domiciled in a country or place that does not require an formal grant to be obtained for the purpose of administration of a deceased’s estate, in other words, in places where the concept of grant does not exist at all.
For the deceased of Mainland, applications require evidence on foreign law showing an applicant’s entitlement to administration or to a grant according to the law of the place of a deceased’s domiciled, as r.29(b) applies.
Along with this rule, r.38(1)(f) requires a guarantee given by two sureties as a condition of granting administration to an applicant who is resident elsewhere than in Hong Kong. An application to the Registrar may be made to dispense with this requirement.
(c)    if there is no such person as is mentioned in paragraphs (a) and (b) of this rule or if in the opinion of the Registrar the circumstances so require to such person as the Registrar may direct.
The rule under r.29(c) usually applies in respect of those countries or places in which a grant is required to administer the estate at the country or place where the deceased died domiciled but no such grant has been made because, for example, no estate is left there.