The Government have walked back empty-handed from the latest carbon auction- creating a $500 million shortfall.

Polluters had the option to purchase the 'rights' to produce units to offset their emissions.

The Government could have earned $512 million by selling the 8.95m carbon units on offer, double the usual amount after losing the March auction.

Climate Change Minister James Shaw explained that there wasn't enough demand at a price they were willing to sell.

"There's a lot of over-supply in the system at the moment, and I think that the last auction failed to clear that- volume got added to today's auction, which essentially doubled the size of today's auction."

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