Whether redundantancy payment is taxable?

The question itself depends on your employment contract. There is a redundancy, terminal bonus etc., the deductibility of which depends on how the staff got that lump sum and whether that lump sum relates to a contract bonus. Without any information on the employment contract, it is hard to say whether it is non-taxable. On the face of it, a redundancy payment is not taxable but it really depends on what the conditions in the termination.
Hope it can be of help!

Any payment in lieu of notice that you receive from your employer that ispaid in accordance with the terms of your employment contract or the provisionsof the Employment Ordinance is not income relating to a service provided by anemployee and is thus not taxable.

http://www.gov.hk/en/residents/taxes/salaries/salariestax/chargeable/termination.htm