An unknown number of Oculus VR customers have been forced to wait a little longer for the Rift virtual reality headset after Facebook said it had been hit by "an unexpected component shortage"—thereby delaying some of its shipments.

Oculus—in an update—promised to, er, update customers who have been affected by the hold-up within the next week.

Facebook—which last week began delivering the virtual reality units trumpeted by boss Mark Zuckerberg as "the most social technology ever"—hasn't revealed how many orders were hit by the shipments delay. Oculus said in an e-mail to customers on Saturday:

We know you're anxious to receive your Oculus Rift, and apologise for not updating your order status sooner. We've been working through an unexpected component shortage, and unfortunately, that issue has impacted the original shipping estimates for some early customers. We're working hard to get up-to-date ship windows, and you should expect to see your order status updated on oculus.com by Tuesday, April 12. Although many Rifts will be arriving on schedule and in line with original estimates, we'll be covering shipping and handling costs for all orders placed through today.

Oculus CEO Brendan Iribe acknowledged that shipments were clogging up. "First set of Rifts are going out slower than we orig estimated, so we're giving free shipping for all pre-orders, including international," he said in a tweet.

If you haven't yet ordered an Oculus VR headset, the expected shipping date is now sometime in July.