A former insurance company senior marketing manager has been jailed five years for swindling $15.7 million from the firm with inflated and falsified invoices.

Winnie Sin, 41, formerly employed by Prudential Assurance, was found guilty of two counts of conspiracy to defraud, and two of dealing with property known or believed to represent proceeds of an indictable offence at District Court today.

Co-defendant, Lee Wai-li, 54, who had earlier pleaded guilty to similar charges, received a two-year jail term.

The court heard that Sin issued a number of orders to a printing company for Prudential between November 1997 and October 2000. She also instructed some people to inflate or falsify invoices of various companies, some of which were under her control and operated by her relatives, including Lee her aunt.

Sin submitted the invoices with those of the genuine printer for claiming payments. As a result, Prudential paid $18.2 million, of which only a small portion actually went to the genuine printer while the remainder went to those companies issuing the false invoices.

The inflated amount of $15.7 million was subsequently deposited into Sin's personal bank account.

Judge Peter Line reprimanded Sin for a serious breach of trust which warranted an immediate custodial sentence. He said Lee was given a lesser jail term in view of her relatively minor role in the case.