In NZ it is more easy to get your motorbike insured. I had following insurance company but after reading some prices on this site also about same company I definitly paied too much so negociating is necessary :
John Baker Insurance Broker
33-37 East Tamaki Rd.
tel. 09/ 278 62 64
fax. 09/ 278 53 02
I payed 300 NZ$ for 3 months and another traveller only paied 100 NZ$ for 3 months and 2 motorbikes (if this price was correct off course).
I arrived in Sydney and got my insurance at Kings Cross Car Park Ltd, the insurance company was Lumley General Ltd., Lumley house, Level 9, 309 Kent Street, Sydney NSW, tel 02/9248 1111, fax 02/9248 1122 and I paied 175 AU$ for 4 months.
New Zealand, Australia & Tasmania - 2003 - 40.000 km on my own
Next: South America - sept 2008-march 2009