Yes, that's not even what the NZRB's own 2018 size and scope report says. GDP is not mentioned in relation to that dreamed up number, and much of that is from nothing to do with racing:
In 2016/17, the New Zealand Racing industry
generated total direct spending of $1,205.8 million.
This expenditure was responsible for creating a
direct value-added impact (in terms of wages,
salaries and profits) of $611.0 million. However, the
flow-on effects linked to this expenditure increase
the size of the industry’s value-added contribution
to over $1.6 billion.
Direct expenditure is defined as expenditure associated with producing foals and pups (breeding & rearing), preparing racing horses and
greyhounds (training), racing customer expenditure and expenditure by NZRB, the three codes of racing and racing clubs on operating the industry.
Direct expenditure is counted at the point at which it leaves the racing industry and reaches the broader economy.
2
Value-added contribution
is defined as the value of sales less the value of inputs used in production, i.e. it is equal to the income (wages, salaries and profits) generated in
production
3
Household Income is defined as being wages and salaries (before tax) earned from employment generated by the racing industry