If a police officer walks up to you and request to check your mobile phone, you cannot refuse, they have more powers than your partner or spouse. According to the Communications and Multimedia Act 1998 under  Section 233, the Police personnel can inspect mobile phones belonging to individuals to ensure there are no forms of communications that are obscene, offensive, or threatening to the security of the people and nation. 
This was allowed to maintain public order, under the law. However, the public should also be aware of their rights during a random check, including requesting the identity of the police officer conducting the search for record purposes, in case there is a breach of the standard operating procedures (SOP).  If an individual felt the police personnel had violated any SOP, they could report it to the nearest police station or at Bukit Aman.

Not only that, the police could also use any means including ‘phone bugging’ or ‘tapping’ in order to ensure investigations could be carried out in cases involving security. During a question and answer session in Parliament, Deputy Home Affairs Minister iterated that It does not matter if the person is a politician, a businessman or just anyone if the person is suspected of having the potential to breach security issues, the police will take the appropriate action.

So be careful what you watch or use your mobile device for when in public, all you need is someone to complain and you could end up with a fine or even jail term.

Another useful public service announcement from LiveatPC.com.