"Good little afternoon," quipped alleged insider trader Oliver Curtis after making almost $70,000 in a day.

Taped telephone calls played on Monday at the criminal trial of Mr Curtis, husband of Sydney public relations queen Roxy Jacenko, show the ease with which the young banker made tens of thousands of dollars betting on the share market.

"I'm just on the golf course getting another beer," he said as he gave instructions to his broker in one call in February 2008.

In another, recorded in April 2008, he said of a relatively insignificant trade: "It's f--k all. Made a couple of grand."

Mr Curtis, 30, has pleaded not guilty to a charge of insider trading stemming from a deal he allegedly struck in 2007 with his former best friend John Hartman to exploit confidential information to cash in on shifts in share prices.

The NSW Supreme Court has heard the St Ignatius College Riverview old boys, then in their early 20s, made $1.43 million in a year.

On Monday the court heard Mr Curtis used a firm called CMC Markets to buy and sell so-called contracts for difference, which allow traders to profit from betting on movements in share prices.

Phone calls between Mr Curtis and the firm, which routinely recorded its calls with clients, show he enjoyed the perks of valued clientele including lunches with traders and flights to Melbourne in 2007 for Derby Day.

"You fly me down and then I'll cover the costs for the room and stuff," Mr Curtis told Andrew Knight, then a sales trader at CMC.

In an October 2007 email, subject lined "Oli 'CMC' Curtis", Mr Hartman joked Mr Curtis could rival a famous trader who made $1 million in 1907 or "about 3 billion in today's money".

"Could be you through CMC," Mr Hartman said.

In one phone call, recorded on December 20, 2007, a trader told Mr Curtis he had made "about $67,000 which is a nice trade".

"Cool. Good little afternoon," Mr Curtis said.

Mr Knight told Mr Curtis in an August 2007 call he had made "24 grand" in another "nice afternoon trade".

"That'll do, that'll do," Mr Curtis said.

"That'll stand you in good stead for the weekend," Mr Knight replied.

But it wasn't always smooth sailing for the young investment banker. Mr Curtis lamented in one call that he had "f--ked up" trades relating to logistics group Brambles.

"I left a bit of f--king money on the table, yeah?" Mr Curtis said, adding he was in "struggle town".

The case has pitted former friends against one another as Mr Hartman, who has already served a jail sentence for insider trading, appeared as the prosecution's star witness.

Mr Hartman has admitted he used confidential information acquired during his job as an equities dealer at boutique investment firm Orion Asset Management to profit on the share market.

But Mr Curtis has denied entering into an illegal deal with Mr Hartman to use the information.

The trial continues before Justice Lucy McCallum.