Bungled technology projects that were supposed to slash expenses by centralising IT systems for the state's transport agencies have, in fact, led to a surge in annual operating costs.

The Herald can reveal that Transport for NSW's IT group blew its annual operational budget of about $30 million by more than $80 million in the 12 months to June.

The troubled $1 billion technology upgrade impacts the running of the state's transport, including roads. Credit:Michele Mossop

That followed a $40 million blowout in the operational budget from about $30 million in the previous financial year.

And the surge in annual operating costs is likely to continue because a $1 billion technology systems upgrade has failed to live up to expectations amid rapidly increasing demands on IT from transport agencies and the users of their services such as commuters and motorists.