There is no provision for shift allowance under the Employment Act. It is mostly up to the employer to consider. You may request for some shift allowance especially for the 5am shift because of the hardship of getting up so early. But remember, there is no law.
KL Siew has put up a sister site by the name of mylabourlaw.net, which is in effect a more user-friendly version of the present popular pesaraonline.net. The site is in the process of being fine-tuned but it is fully functional. You are invited to visit the website at http://www.mylabourlaw.net and give your views or suggestions. Queries can be posted and be responded from there as usual.