31 March 2011: Filing deadline - NZ income tax with extension of time for filing returns for the year ended 31 March 2010.
7 April 2011: Payment deadline - NZ income tax with extension of time for payment - terminal tax for the year ended 31 March 2010.
18 April 2011: Contributions to IRAs: if you wish to make a deductible contribution to your traditional IRA, you need to make it by 18 April 2011. Note from editor: it is acknowledged that many people who reside outside the United States are unlikely to be making contributions to IRAs.
If you pay estimated tax you must make instalment one for 2011 unless you derived more than 2/3rds of your income from farming or fishing.
If you have end of year tax to pay for 2010 you must pay by this date to avoid late filing penalties and interest.
If you are a non-resident alien and you had wages in 2010 that were subject to withholding, you must file a US tax return by 18 April 2011.