Supplies of the MacBook Air around the world are drying up as Apple reportedly prepares to launch new models.

9to5Mac said that sources around the world have told it that supplies of the MacBook Air are dwindling ahead of an expected refresh for the product line.

Back in April, Macworld reported that new MacBook Air models were likely to be on the horizon, perhaps launching in June.

However, the most significant additions to the new MacBook Airs are likely to be Sandy Bridge processors and Thunderbolt ports.

Many of the MacBook Air's rivals in the thin-and-light category such as MSI, Dell, Lenovo and Samsung are either already using Sandy Bridge processors or are about to introduce them.

Meanwhile, shipments of the Airs declined 51 percent sequentially during the first calendar quarter of 2011 — including a 40 percent month-on-month drop in February — as Apple introduced new MacBook Pros.

All MacBook Air models ordered through the UK Apple Store website will ship within 24 hours, with a similar waiting time listed on the US website. Refurbished models are on sale for as little as £734 in the UK and $829 in the US.

On, all of the MacBook Airs listed are low in stock, with only five 11-inch models and two 13-inch models available.