Accenture is New Zealand Inland Revenue's preferred provider of design services for the first stage of its NZ$1.5 billion business transformation program.
The consultancy beat the otherfirm, Capgemini, which has already worked on earlier stages of the massive project.
Commissioner Naomi Ferguson described the program as a business-led, technology-enabled transformation, which will see nearly every part of Inland Revenue redesigned.
Ferguson said Accenture has designed and implemented systems of similar scale before.
"Throughout the procurement process, Accenture clearly demonstrated it had the right capabilities, capacity, and experience to assist Inland Revenue," she said.
Deputy commissioner change at Inland Revenue, Greg James, said the program will reduce compliance, administration time, and costs; deliver better services for customers; and make it easier for the government to implement policy.
Inland Revenue will now commence negotiations with Accenture, which are expected to be completed following Cabinet's consideration of the Transformation Design Business case.