As an employer I would have to say that 1 month can look like a joke... depending on the industry.
If it is a situation where the employer will be opening up their internal operating situation to you in a way that would be of value to their competitors then they would be sensible to have enough 'buffer' time for that knowledge to have lost value - this is the purpose of those clauses.
Of course, that does not apply to many situations, but does in some.
It is accepted in NZ law that 6 months is a maximum amount of non-compete before it is considered restraint of trade, and also that you can only restrain against working for a company that does or is likely to compete directly within that timeframe.
Another question is does the time start from when notice is given (by either party) of frm the final date of employment, this can make a big difference.
As stands three months is way to long I will propose 1 month as ok
Thanks for your input Carl
Supra Club of New Zealand - http://www.supras.org.nz/
Website sponsored by Alltech Diesel & Turbocharger http://www.turbo.co.nz