NSW Transport Minister Gladys Berejiklian has been accused of giving jobs to the boys and misleading parliament, after nearly $500,000 worth of work was awarded to a former colleague.

Labor MP Luke Foley wants an investigation into the awarding of a government contract to the consultancy firm Conrad Capital last year.

Jack Simos, who worked alongside Ms Berejiklian as a staffer for the then NSW Treasurer Peter Collins, is CEO and managing director of the firm.

In a budget estimates committee meeting last month, Mr Foley said he had quizzed Ms Berejiklian about the "fat contract" but she had denied any involvement, saying everything was handled by her department.

However, Mr Foley said documents reveal Mr Simos's appointment was actually instigated by her office, and before the firm was even registered for GST.

In March last year Owen Johnstone-Donnet, chief of staff from the minister's office, emailed the Department of Premier and Cabinet requesting their help to engage Conrad Capital to "undertake special tasks in relation to transport reform".

He said the two principals of Conrad Capital - Richard McKinnon and Mr Simos - "would report to and be accountable" to him.

"I think it's not only a question of jobs for the boys but also a question of ministerial responsibility to the parliament," Mr Foley told reporters on Tuesday.

In failing to reveal her office's role in the appointment, he said it appeared the minister misled the parliamentary committee.

Mr Simos's firm was initially engaged for three months work at $10,000 per month, which meant it did not have to go out to the market and seek quotes.

A further $290,000 worth of work his firm was then awarded was based on the three-months of previous experience.

All up, Mr Foley said the firm had been awarded $485,000 in payments.

"I'm calling today on Premier (Barry) O'Farrell to investigate this highly irregular contract driven not by the public service but by a minister's own private office," he said.