a. It is based on a specific writ known in full as “habeas corpus ad subjiciendum” (literally translated as, you should have the body for submitting).
In Chua Kian Voon v Menteri Dalam Negeri Malaysia & Ors  MLJU 1491 [“Chua Kian Voon”], the Federal Court remarked that:
“The term habeas corpus refers most commonly to a specific writ known in full as “habeas corpus ad subjiciendum”, a prerogative writ ordering that a prisoner be brought to the court so that it can be determined whether or not the prisoner is being imprisoned lawfully … The words “habeas corpus” is a Latin law term. Its literal English translation is: “you have the body”.”
b. It challenges the legality of a detainee’s detention.
The Federal Court in Chua Kian Voon summarised habeas corpus applications as follows:
“Put simply, a writ of habeas corpus is a challenge to the legality of a prisoner’s detention.”
Challenges to the competence of the detaining authority would also fall under the scope habeas corpus application. In Jaideep Singh Dalip Singh v ASP Mahathir Abdullah Sapawi & Ors  3 MLJ 1, the Federal Court held:
“… where a challenge is made to the competence of the detaining authority to detain a person for want of the requisite powers to do so, such a challenge can be made by way of an application for a writ of habeas corpus. This was what happened in the present case. The appellants were challenging the competency of the detaining authority, who happened to be a magistrate which was vested with the powers under the POCA. Such powers under the POCA is not synonymous with the magistrate executing his powers under the Subordinate Court Act 1948.”
c. It is granted as of right if the Court finds that a detainee is improperly or illegally detained.
This was expressly stated by the Federal Court in Chua Kian Voon:
“The writ of habeas corpus must be issued if the court finds that the detenu is illegally or improperly detained.”
d. The burden lies with the detaining authority to show that the detention is legal.
In SK Takaliswaran Krishnan v Menteri Dalam Negeri, Malaysia  6 CLJ 705, Gopal Sri Ram JCA (as His Lordship then was) opined:
“It is settled law that on an application for habeas corpus the burden of satisfying the court that the detention is lawful lies throughout on the detaining authority.”
e. If the detaining authority satisfies the burden, the onus then shifts to the detainee to show otherwise.
In Chua Kian Voon, Mohd Zawawi Salleh FCJ observed that:
“After the party who made the detention succeeded in proving that the detention is in accordance with the law, the onus then shifts to the detainee, especially if he alleges bad faith (see: Karam Singh v Menteri Hal Ehwal Dalam Negeri, Malaysia  2 MLJ 129).”
f. The detainee is entitled to take advantage of any technical defect which has the effect of invalidating the detention.
The Supreme Court in Ng Hong Choon v Timbalan Menteri Hal Ehwal Dalam Negeri & 1 Lagi  3 MLJ 285 said in passing that:
“… in cases of this nature [i.e. a habeas corpus application] the appellant is nevertheless entitled to take advantage of any technical imperfection which has the effect of invalidating the restrictive order.”
This position was recently affirmed by the Federal Court in Chua Kian Voon.
g. The High Court has original jurisdiction.
Article 5(2) of the Federal Constitution provides that:
“Where complaint is made to a High Court or any judge thereof that a person is being unlawfully detained the court shall inquire into the complaint and, unless satisfied that the detention is lawful, shall order him to be produced before the court and release him.”
Additionally, Section 365(1) of the Criminal Procedure Code prescribes that:
“The High Court may whenever it thinks fit direct-
(1) that any person who:
(a) is detained in any prison within the limits of Malaysia on a warrant of extradition whether under the Extradition Act 1992 [Act 479]; or
(b) is alleged to be illegally or improperly detained in public or private custody within the limits of Malaysia,
be set at liberty;”
h. Appeals are directly to the Federal Court.
Section 374 of the Criminal Procedure Code provides the following:
“Any person aggrieved by any decision or direction of the High Court under this Chapter may appeal to the Federal Court within thirty days from the date of the decision or direction appealed against.”
i. Applications can be limited in scope as a result of statute.
This was impliedly acknowledged by the Federal Court in Chua Kian Voon.
For example, Section 15B(1) of the Prevention of Crime Act 1959 excludes judicial review of the Board’s act (which in the Act is defined to include habeas corpus applications) except in cases of procedural non-compliance.
j. Could possibly be suspended by Parliament but must be done so expressly or by clear implication.
The Court of Appeal in Sukma Darmawan Sasmitaat Madja v Ketua Pengarah Penjara Malaysia & Anor  1 MLJ 266 referred to the decision of the United Kingdom’s Court of Appeal in R v Governor of Pentonville Prison & Anor, Ex parte Azam  2 WLR 949 whereby Lord Denning MR noted:
“These provisions as to appeal give rise to a question of the first importance. Do they take away a person’s right to come to the High Court and seek a writ of habeas corpus? I do not think so. If Parliament is to suspend habeas corpus, it must do so expressly or by clear implication.”