"We have started destroying" the vaccines, health ministry spokeswoman Inge Freriksen told AFP. "In the coming months, 17.8 million doses will be destroyed because the expiry date is approaching."
The Dutch government bought 31 million doses of vaccine against the A(H1N1) virus at the height of the global swine flu outbreak last year. About 11 million were used.
Some 2,156 people infected with swine flu were hospitalised in the Netherlands between April and December last year and 53 died.
In November the Dutch government said it was putting 19 million doses on sale to other countries, but managed to offload only 257,000.
The government will keep 2.2 million doses with a later expiry date "in case the virus returns in one form or another", Freriksen said.
The World Health Organisation declared a swine flu pandemic on June 11, 2009, and says it has since claimed some 18,311 lives worldwide.
The Council of Europe recently called for a probe into the WHO's handling of the outbreak, which it said caused unjustified scares and waste of public money.