By Phil Mercer in Sydney

The company expected to rebuild Wembley stadium is one of several firms which have been asked to contribute to an investigation into alleged corruption and fraud in the Australian construction industry.

Multiplex, a privately owned enterprise based in Perth in Western Australia, is expected to be given the go-ahead to lead the troubled national stadium project - although further delays have put a decision back until April 2002.

The company is one of six Australian construction giants who have been called to give evidence to a Royal Commission set up by the federal government.

The inquiry will also examine the highly sensitive area of trade union power.

Union power

So far Mulitplex and the other major companies have refused to take part in the investigation.

The trade unions are not keen to participate either.

The commission has obtained court orders compelling two union officials to give evidence.

It is estimated 200 people could be forced to speak to investigators.

The company also built the Emirates Tower in Dubai

Industry sources claim fear of the union movement has kept the big firms away.

"It's the law of the jungle," one insider told BBC News Online.

"There's so much at stake and the unions are so powerful it would be suicidal for some companies to turn up voluntarily," he said.

There has been no comment so far from the Multiplex boss, the 69-year-old Australian businessman John Roberts, the man who could soon have control of the new Wembley.

Union leaders have described the Royal Commission, lead by Terence Cole QC, as a "government-sponsored witch-hunt".

About 1,000 construction workers gathered outside the hearing in Melbourne last week to voice their anger.

"It's understandable the unions don't want to be investigated," says Bob Herbert, the chief executive of the Australian Industry Group, which represents large companies.

He believes the building sector has been "fraught with problems in recent years, especially in Victoria, where there has been massive industrial confrontation."

Private company

The Royal Commission will delve into the murky world of the Australian building trade.

Workers, unions and companies are all under the microscope.

It is one of the most far-reaching inquiries of its type in recent times. Its report will be published in December next year.

Multiplex is a private company and is not required to publish annual accounts. Industry experts estimate its turnover to be in excess of �400m.

Multiplex built Stadium Australia, the jewel in the crown of the Sydney Olympics, and received the coveted Sir William Hudson Award for its efforts.

It has built a string of hotels across south-east Asia.

In Dubai it built the Emirates Towers, a giant piece of engineering standing 55 metres taller than the Eiffel Tower.

It constructed the highly regarded Supreme Court and Parliament House in Darwin, Australia

Closer to home in Australia, Multiplex is responsible for the highly regarded Supreme Court and Parliament House in the Northern Territory capital, Darwin.

The Australian company has offered to raise much of the construction costs to kick-start the stalled Wembley project.

In return it wants to lease the new 90,000-seat stadium back to the Football Association for 25 years.

The Culture Secretary Tessa Jowell told the Commons she had serious concerns about the entire project, including the way it has been managed.

She said if the Multiplex contract was to be continued, an independent assessment was needed to make sure �120m of lottery money was protected.

FA chief executive Adam Crozier said a final decision would be made in April.

Multiplex was approached by BBC News Online but declined to comment on the inquiry.