As Premier Mike Baird on Wednesday was asked more questions about the company and its dealings with the NSW government it has emerged that State Grid Corp's president, Liu Zhenya, was named as a key focus of the probe.

Mr Baird's office confirmed that a State Grid Corp executive, Shu Yinbiao, was one of those present at a business roundtable addressed by Mr Baird during his trip to China in September, not its president Mr Liu as previously advised.

In May the South China Morning Post reported the "massive audit" was in response to authorities receiving letters "alleging financial problems and accusing the power company's management of potential corruption".

The newspaper said the audit would last "at least until October", raising the prospect the company remained under investigation when Mr Baird addressed the roundtable hosted by the Australian ambassador.

Reuters reported last June that State Grid confirmed the audit – involving 1000 investigators – but dismissed it as "routine".

However, the Wall Street Journal said in June the audit, which also involved another state-owned electricity company, China Southern Power Grid Company, focused on contracts for a west-to-east electricity transmission system.

The newspaper said China's national audit agency alleged that "more than $1 billion was misappropriated in less than four months [during 2013] in the construction and running of portions of a major electricity grid system".

Asked if Mr Baird knew about the revelations before his China visit, his office said it had "no further comment".

Fairfax Media can reveal that State Grid Corp's attendance at a roundtable addressed by Mr Baird was omitted from an official report on his trade trip to China last year.

Mr Baird on Wednesday repeatedly refused to detail meetings held during the trip to China last September, which aimed to drum up interest in NSW infrastructure projects.

The Coalition government's plan to partially lease the electricity "poles and wires" and spend the proceeds on infrastructure is the centrepiece of its re-election campaign.

The unions and Labor have questioned the appropriateness of a foreign power owning NSW electricity businesses, a deal which some fear would have national security implications.

Under Mr Baird's reforms to political lobbying, ministers are required to publish details of external meetings.

But on Wednesday Mr Baird said the rules did not apply to trips abroad, saying "there's a different process for international trips, that's well established".

A spokesman for Mr Baird later said the Department of Premier and Cabinet had been advised that details of ministers' meetings on official overseas missions "should not be disclosed through the ministerial diary process as there is appropriate disclosure of such meetings through mission reports".

However the mission report from Mr Baird's China trip does not mention a meeting with State Grid Corp.

Asked later on Wednesday why the meeting was omitted, Mr Baird said he had complied with disclosure obligations for overseas trips.

At the news conference he declined to say who else was at the September roundtable meeting.

"I am not going to go into individual meetings. As Treasurer and Premier I met with hundreds if not thousands [of potential investors]. My job is to encourage investment into NSW," he said,

Opposition leader Luke Foley said Mr Baird was "trying to skate through to Saturday without facing the scrutiny his privatisation policy deserves".