Butter, of all things, has become a precious commodity in Norway these days, with a shortage of the slippery spread leading to black market sales, astronomical price offers and even smuggling.

One man in Lillehammer claimed he was offered 3000 kroner ($US515) for his “almost unused” half-kilo stash after placing an ad on a buy-and-sell internet site, The Local Norway reported. He later claimed he posted his ad as a joke.

Another would-be butter vendor, seeing no margarine for error, asked a minimum of 800 kroner ($US137) in an online auction.

The butter shortfall is expected to last through the holiday baking season and into January, according to AFP.

The reason behind it is more difficult to pin down. One theory is that a rainy summer reduced feed production and therefore dairy output.