(1) Notwithstanding anything contained in section 29, where fraud or willful neglect has been committed with a view to evade or avoid the payment of tax or due tax has not been paid or a return has not been filed by or on behalf of a person, the designated officer may, for the reasons to be recorded in writing, make provisional assessment for any period to determine the tax liability so evaded, avoided or unpaid:
Provided that tax liability of such a person shall be assessed finally after he files his return in the prescribed manner.
(2) The provisional assessment under sub-section (1) shall be made within a period of six months from the date of detection. The Commissioner may, however, for reasons to be recorded in writing, extend the said period by another six months in a particular case referred to him by the designated officer.