Employer wants me to sign resignation letter or be sacked, is this legal?

From my experience, do NOT sign anything on the spot under pressure. Forcing you to resign under threat can amount to 'constructive dismissal' or an unlawful termination, and if you voluntarily resign, you may lose the right to claim. In Malaysia, an employer generally cannot just dismiss you without just cause or excuse, and there's usually a process (show cause, domestic inquiry for misconduct). Ask for the allegations in writing and time to respond. Politely say you need time to consider and will not sign today. Keep all documents and messages. You can lodge a complaint at the Industrial Relations Department (Jabatan Perhubungan Perusahaan) within 60 days if unfairly dismissed. This is a legal matter with deadlines, please consult a lawyer or the Labour Department quickly, many give initial advice cheaply or free.

I went through something similar, and the number one rule is don't sign the resignation under duress. Once you 'resign', it's much harder to claim unfair dismissal. Employers sometimes pressure staff to resign precisely to avoid a proper termination process and paying benefits. In Malaysia, dismissal must be for just cause and excuse, with due process. Tell them calmly you'd like the concerns in writing and time to think, you're not obligated to decide immediately. Save emails, your contract, payslips and any evidence of your performance. If they still push, you can file a representation for reinstatement at the Industrial Relations Department, note there's a 60-day time limit from dismissal. Please get proper legal advice fast, a labour lawyer or the JTK (Labour Department) can guide you on your specific situation.