If any person being required or authorised by law to make any statement on oath for any purpose, and being lawfully sworn wilfully makes a statement which is material for that purpose and which he knows to be false or does not believe to be true, he shall be guilty of a crime and offence and shall be liable on conviction thereof to penal servitude for a term not exceeding five years or to imprisonment with or without hard labour for a term not exceeding two years or to a fine or to both such penal servitude or imprisonment and fine.