Nicolas Steenhout wrote in message
. ..
As I'm preparing to move to New Zealand, I have to get my pots ready to
go. They have been power washed with pressure hose, but I also want to get
them sterilised before packing them. This is not a requirement from the
Ministry of Agriculture and Forestry, but I hear through the "grapevine"
that if you do sterilise them and outline the procedures you've taken they
are less likely to want to fumigate the pots and charge an extra $100-$500
for fumigating on entry.

How about emailing the authorities in NZ and asking what they recommend?
Something along the lines of,
"I'm going to arrive in NZ on X date bringing used bonsai pots. How would
you recommend sterilising them?"

Could work?

Cheers,
Heidi Aussie