It is now mandatory for oil companies to sell a minimum percentage of biofuels.
Under the Government's biofuels sales obligation policy, 0.5% of the combined petrol and diesel sold by fuel companies over the next year has to be biofuel.
The policy is part of a biofuel bill passed by Parliament under urgency in September, which aims to increase the use of renewable transport fuels. It takes effect from 1 October.
Decisions about which type of biofuel is used, how much of it is blended with fossil fuels, and where it comes from are up to each company.
However, Chevron New Zealand, which markets Caltex, says it cannot start building the infrastructure needed to import the fuels until the policy is guaranteed to remain in the future.
It says National has stated it will scrap the policy if it is elected on 8 November.