The Victorian State Revenue Office (SRO) is conducting a mammoth 10-year Service Orientated Architecture (SOA) implementation to revitalise its central payment systems.

The SRO is an independent service agency which collect taxes, duties and levies under an agreement between the Victorian Treasurer, the Secretary of the Department of Treasury and Finance, and the Commissioner of State Revenue. It collected $8.6 billion in revenue during 2006 - 2007.

The project began in late 2005 with the goal of improving the efficiency of IT delivery within the SRO and to its dependent agencies, expanding the use of electronic delivery and in reducing compliance costs to taxpayers.

SRO IT director Chris Howard has adopted a transitional deployment of SOA over four years, because a large amount of modification and continual tweaking is required to match changing business requirements.

"The business case will take us until the end 2010. It is a high-level plan which each year clarifies our work and shapes the next 24 months, so we don't have to continually change direction," Howard said.

"The SRO was able to extend the life of [it's tax payment system] without the significant investment involved in re-writing a new application or purchase of an off the shelf product.

"We're exploring how SOA can provide us with greater integration within our architecture, including internal and external connections with our core applications, and how it can couple our services so we can better develop applications that support the businesses."

The project will allow agencies dealing with the office to add a small layer of code for their applications to be interoperable with SRO architecture, including its two core payroll tax application systems, e-Sys and e-Business, commonly known as Payroll Tax Express and Land Tax Express.

E-Sys is the SRO's core revenue management system which processes Victorian taxation legislation and collection of taxes, duties and levies. The Web front end application, e-Business, is used by over 20,000 business taxpayers a month.

The office will be able to integrate its applications with the depositories of external agencies and its own using a service bus and standard interfaces.

The IT makeover won't be easy, according to Howard. The SRO IT team must surgically nip and tuck the entire core code architecture, ensure its applications are interoperable with each other and between external agencies, while still increasing functionality.

Rip and replace of legacy systems has been banned, and IT must also avoid down time and disruption to customer facing applications.