An opposition MP has blasted Home Minister Ahmad Zahid Hamidi's refusal to explain the use of the draconian Security Offences (Special Measures) Act 2012 (Sosma) on Bersih chairperson Maria Chin Abdullah as "irresponsible".

Zahid yesterday dodged questions on Maria's detention under the Act meant for high-level security threats, saying the question was an "operational matter" that should be directed at the attorney-general (AG) and the inspector-general of police (IGP).

"It is irresponsible of Zahid to try to avoid all explanation by claiming that the arrest is an ' operational' matter.