Auckland, March 18 NZPA - A former investment banker who stole nearly $18 million in the country's largest employee theft has been jailed for six years.

Stephen Gerard Versalko, 51, was sentenced in Auckland District Court today after previously admitting nine years of stealing from 30 wealthy ASB Bank customers.

The court was told that $3.4 million of the stolen money was spent by Versalko on two sex workers.

Versalko was ordered to serve at least four years before becoming eligible for parole.

His guilty plea on three charges involving $17,763,108 made him the largest employee thief in New Zealand history, surpassing the $16.9m fraud by a manager at Otago District Health Board.

The three charges Versalko admitted were:

* Obtaining $12,958,608 from 17 ASB Bank clients by conducting 68 fraudulent transactions between October 2003 and August 2009;

* Offering fictitious investment opportunities to obtain $1,074,077 in 12 fraudulent transactions between August 2000 and September 2003;

* Obtaining $3,730,423 from 28 ASB clients by conducting 43 fraudulent transactions between October 2003 and April 2009.

Versalko, a senior investment adviser with the bank, was fired last August and arrested a few days before Christmas.