All returns made under this Act and all remittances of the tax (and any correspondence resulting from or connected with any such return or remittance) may, if posted in Malaysia in envelopes marked "Real Property Gains Tax", be sent free of postage to the Director General, to the Director of Inland Revenue, Sabah, to the Director of Inland Revenue, Sarawak, or to an officer or address specified in an order made under section 54:

Provided that the Director General may in certain cases by notice in writing require any person to send any return, remittance or correspondence by registered post.