Some fear that the date June 6, 2006, signifies 666, the biblical number of the beast, and will usher in calamities or even the end of the world.
Ambassadors Ministries, a group based in the Netherlands, called its 24-hour prayer vigil from 6pm (1600 GMT) on Monday, saying it hoped that about 2,000 Dutch Christians, would take part.
The organisation said on its website: "We believe that the plans the enemy has for this date [June 6, 2006] will be destroyed through violent worship and praise. We are inviting the entire world to be part of this huge unity project."
Mathijs Piet, a member of the organisation, told AFP: "The forces of evil are using this day. Through our action we want to stop them from achieving their goal."
The figure 666 is called the number of the beast in the closing chapter of the Bible, the Book of Revelation, also known as The Apocalypse of John.
Chapter 13, verse 18 of the book, with its apparent reference to the coming of the Devil, has long interested demonologists and fed the fantasies of conspiracy theorists and writers of ghost stories.
Violent Day of Worship - Ambassadors Ministries