We hope that Judges should endeavour to write their grounds of decision and take delight in this aspect of judicial work as a matter of personal pride and satisfaction and not as a burden. Failure on the part of Judges to write their grounds of decision will certainly undermine their authority to insist upon Magistrates and Presidents of Sessions Court to write theirs. If the practice of not writing grounds of judgment is widespread the system of administration of justice will tumble down.
per Salleh Abas LP in Wong Chee Hong v Cathay Organisation (M) Sdn Bhd  1 CLJ (Rep) 298 at 300
As a matter of course, Judges should write and give reasons/grounds for their decisions (usually known as “Alasan-Alasan Penghakiman”).
The courts have an obligation to explain how the decisions made have been made or arrived at.
Litigants are entitled to understand why they lost or won. After analysing the reasons/grounds, they may wish to file an appeal or to review the decision(s).
Lawyers and academics are interested in how the facts of the case were interpreted, and how the submission of counsel and the finer legal points were dealt with.
Importantly, and particularly in cases of public interest, the public must be able to read and examine for themselves the reasons/grounds to educate themselves and be mindful as to how the laws are applied in the country.
The Perak crisis has seen the Federal Court make several landmark rulings on constitutional points which have not previously been decided in the country; see a summary of the cases here. Despite requests made to the Federal Court, no reasons/grounds of its decisions have been forthcoming (but instead has been refused in the Nizar section 84 instance). Lawyers for either side do not know on what grounds, and why the matters were decided the way they have been decided. No further appeals or reviews may be advised because the reasons/grounds have not been supplied.
In the Nizar v Zambry matter, the learned High Court Judge, His Lordship Justice Abdul Aziz Bin Abdul Rahim has already written two “Alasan-Alasan Penghakiman” – first, on granting leave to commence judicial review proceedings on 3.4.2009 (16 pages) and second, on granting the orders sought by Nizar on 11.5.2009 (finalised written grounds are due to be supplied next week).
Judicial precedent plays an important role in the development and application of the law in Malaysia as it provides future guidance for the courts, legislature and government(s). Decisions of the highest court especially in matters of public interest and constitutional importance must be sufficiently explained and supported by cogent reasons/grounds. Decisions which are not properly reasoned may be critiqued, and those of sound grounds may be applauded.
Writing reasons/grounds would also assist all to better appreciate the decisions. It may serve as a useful buffer and repellent against unwarranted criticism or cynicism regarding the decisions, and thereby go some way towards shoring confidence in the Judiciary.