Well, if you're asking for the timing or if it should be approved before the start of the fiscal year, there was an old tradition in Westminster countries—one of the most bizarre practices—which was that at one time all Westminster countries routinely approved the budget after the fiscal year had started. That is fading away. Logically, to the extent that a budget authorizes expenditure, it should authorize expenditure in advance of the fiscal year, rather than after the commencement of the fiscal year.
On April 25th, 2012. See this statement in context.