New systems meant customers could expect less time contacting the company, with less human interaction, clearer and simpler digital services and tax transactions through accounting software.
IRD said today it would be restructuring into three new groups - one covering individual taxpayers, families and micro business customers, a second covering small, medium and significant business taxpayers, and an information and intelligence services group.
Staff consultation on the changes ends on May 29.
Inland Revenue Commissioner Naomi Ferguson said there had been a "comprehensive programme of communications" about the changes over the past year.