"They were getting very strong on people pretending to rent," Mr Warren said.
"Now they want evidence their baches are available to rent."
He gets a 75 per cent occupancy rate in December/January through internet site Bookabach which he is "quite happy about" and in winter offers three nights for the price of two.
"If you are not prepared to rent you would have to have a fair bit of money floating about to buy a bach."
Harcourts Wairoa owner Trevor Lyall said the tax changes made little difference to the bach real estate market. Of greater significance was the Global Financial Crisis but the bach market was "certainly recovering".
He lives in Mahia, where most dwellings are baches. Baches were usually sold once family members stopped using them "and another generation will work its way through", but there were up to 30 baches for casual rent at any time.
"Particularly over Christmas, January, Easter and Labour Weekend, people want to rent baches. People that buy baches often stay away in January, to get in on the premium market, and holiday in their own place in February. That pays the insurance, rates and power for the year."
Mr Warren "pops down" for the occasional weekend but prefers travelling.
New Zealand had great weather and an "unbelievable" number of scenic places to visit and stay.
"This country is wonderful for campervans."