The $8 million extension, managed by Sirocom, will last until 2007.
"We have been impressed with the level of service and commitment received from Sirocom," said Claire Reece, vice president of information systems at STA Travel. "Both parties have developed from a relationship into a true partnership based on an appreciation of the evolving requirements of STA Travel."
Sirocom is assisting STA Travel's BLUEe strategy – a project designed to deliver web information through its 400 global offices.
STA's spokesman said that the firm's revenue was more than $1 billion a year. Its 2,500 staff sold tickets to five million travellers last year.
A spokesman fror Sirocom said it had established an office in Australia to meet the needs of the travel firm.