Airport Link project glitches prompted Leighton Holdings Ltd to report an $85 million profit downgrade as the giant construction firm also cited that the rising Australian dollar and issues on its Western Australia rail contract added to its woes.

For the first quarter of fiscal 2011, Leighton said that its expected profit would be hard to realise as chief executive Wal King characterised the Airport Link development as disappointing.

Mr King said that the $4 billion Brisbane project largely handled by Thiess Holland has been hampered by access and engineering issues that resulted to delays and additional projected costs at completion.

He admitted that at its present status, "the problems encountered have contributed to a write-back in the forecast financial outcome of that project."

However, Mr King gave assurance that despite the problems encountered with the Airport Link project, which will connect the Brisbane Airport to the northern suburbs and the Clem7 tunnel, the construction deadline would remain as it is.

He revealed that Airport Link has already passed more than 60 percent of its completion level and the target date of inaugural set by the Queensland state government on the third quarter of 2012 should be achievable.

In partnership with the Queensland government and supported by John Holland, Thiess and the Macquarie Capital Group, BrisConnections has been tasked to build and operate the Airport Link underground toll road for a span of 45 years.

Queensland authorities have allowed a $35 million fund modification for the project following the discovery of soft rock during the tunnelling procedure by Thiess John Holland, which are both subsidiary of Leighton Holdings.

Analysts said that Leighton's reported profit downgrade would lead to a profit after tax of $47 million for the first quarter of 2010/11 that would be contained on the company's detailed financial results set to be released on its annual general meeting on November 4.