Shipments of the XO notebook PC for the OLPC (One Laptop Per Child) project are likely to be delayed until the third quarter of this year, the manufacturer said on Friday.

Quanta Computer, the world's largest contract laptop PC manufacturer, had previously predicted that shipments could start as early as July, but software adjustments by the OLPC group have pushed the schedule back to the third quarter.

"The hardware is pretty much in place," a company representative said.

The firm has already said it has confirmed orders for one million of the laptops. Several nations have already signed up for the project, including Argentina, Brazil, Libya, Nigeria, Rwanda, and Uruguay.

The OLPC project aims to ensure children around the world don't miss out on learning how to use computers. Read more about OLPC here. The fear is that the high cost of PCs is preventing people in developing countries from learning how the benefits of computing can improve their economies, job prospects and lives, a problem commonly referred to as the digital divide.

The group has worked on building a laptop PC, the XO, that costs just $100 (£50), including hardware and software, and comes with a battery recharger and wireless network interface. In many countries where OLPC hopes to distribute the XO, electricity and internet access are bigger problems than the lack of PCs.

The laptop is built to last under rough conditions, is resistant to water and features as few moving parts as possible. Instead of a hard disc drive, for example, which has moving parts, the XO uses flash memory. It's also designed with a tougher outer shell than most laptop PCs, and drop tests have proved the device can survive a few falls. A full list of the hardware specifications shows it also has a Secure Digital memory card slot, three USB ports and an onboard camera.

Critics of the programme, such as Fair International, a Norwegian nonprofit organisation also working to provide PCs for schools in developing countries, complains that the OLPC model is too costly. In addition, some companies argue that the PC should be equipped with the most widely used software so children in developing countries would learn a job-related skill through the machines. Instead, the XO is equipped with a newly developed user interface running on a stripped-down version of Red Hat's Fedora Core Linux OS.

Still, the OLPC project has found a large number of supporters from different walks of life. Many top members of the group are from academia and work at MIT (the Massachusetts Institute of Technology). The project is led by Nicholas Negroponte, a co-founder of MIT's Media Laboratory. And from industry, AMD, Red Hat and Google are just a few of the companies that have joined the initiative.