Support & Confidence from Directors, C-Levels & Non-Executive Directors, page-88

In my experience, yes. The vesting of restricted stock or conversion of performance rights into shares is assessable income in the year that they vest. You can wait until you file your tax return though - your company's payroll won't withhold tax on your behalf. Once you fill in your tax return, you'll get your tax assessment and (cet. par) you'll get a bill.

Should probably add the disclaimer ... get your own tax advice, I'm not a tax accountant