Prime Minister Jan Peter Balkenende's cabinet wants government purchases to be sustainable, Environment Minister Jacqueline Cramer wrote to the Lower House on Thursday. Everything that national bodies buy next year should be sustainable, and provincial and local authorities should follow suit in the long run.

As examples, Minister Cramer suggests that authorities should buy "green electricity", which is generated in a sustainable manner. She also writes that official trips abroad should be made by train if they take less than six hours, and that all office equipment should be energy-efficient.

The measure should yield a reduction of 3 Megatonnes in CO2 emissions and a saving of 20 percent on the government's energy bill.

Government purchases amount to about 40 billion euros a year. By spending the money in a "green" manner, the cabinet is hoping to stimulate the sale of sustainable products and give companies an impetus to innovate, Ms Cramer writes. It is not clear what happens if authorities fail to meet the demands.