An application to put a stop on removal of a child from the jurisdiction is effectively an injunction to prevent removal – usually in high conflict child custody cases – without the leave of the court. Once the order is obtained the Immigration Department is notified and the stop order is entered into the computer system cover all lawful points of entry and exit from Hong Kong.
The old Rule 94 (2) application route under the MCR (Cap 179A) was repealed on 5th April 2016. The reason for the repeal is because on the same date the Child Abduction and Custody Ordinance (Cap 512) (CACO) was amended to reflect recommendations in the LRC Report on “International Parental Child Abduction (April 2002) – never let is be said that HK rushes into amending legislation! There are many substantial amendments to the CACO, including Location Orders (s. 15) Mirror Orders (s.16) Recovery Orders (s.17) and Prohibition Orders (s.21). Of course, most of the amendments attach to Hague applications for unlawful removal. However, the frequently used ex-parte application under MCR r 94(2) on prevention of removal of a child from Hong Kong now arises under Part 3, s.21 CACO (Cap 512) as amended.
See also the obiter remarks of Hon Lam J in PD v. KWW CACV 188/2009;  4 HKLRD 191 at para 78ff, on the urgent need for reform which would make unnecessary recourse to such commonplace applications under Rule 94 –
‘Though the line between sole custody and joint custody is a thin one, it is still one with potential practical significance. A parent with sole custody can determine the place of residence of the child. The other parent, whilst he or she might have a right to be consulted, does not have the power of veto. This could have immense significance in terms of removing a child from the jurisdiction.
Thus, when sole custody is granted to one parent, our courts usually order at the same time that the child shall not be removed from the jurisdiction unless the consent of the non-custodial parent is obtained. This would not be necessary if we have the equivalent of Section 1 of the UK Child Abduction Act 1984. Under that section, it is an offence to take a child out of the United Kingdom without the consent of the other parent or the court. However, notwithstanding the recommendations of our Law Reform Commission in 2002, the proposal has not been implemented.’
See also NP (aka NF) v CTF FCMC 625 / 2011 Per HHJ Sharon Melloy – In so far as access is concerned, this is generally said to be the right of the child, as opposed to the parent.
Other than that the general principles governing applications concerning children apply. See section 3 Guardianship of Minors Ordinance (Cap 13):
Section 3(1) In relation to the custody or upbringing of a minor, and in relation to the administration of any property belonging to or held in trust for a minor or the application of the income of any such property -(a) in any proceedings before any court (whether or not a court as defined in section 2) the court – (i) shall regard the best interests of the minor as the first and paramount consideration and in having such regard shall give due consideration to – (A) the wishes of the minor if, having regard to the age and understanding of the minor and to the circumstances of the case, it is practicable to do so; and (B) any material information including any report of the Director of Social Welfare available to the court at the hearing.