The OGC is charged with saving £1bn a year from public procurement costs and GCat2 is based on framework agreements with manufacturers, consultancy firm and resellers.
These framework agreements allow purchasers to short-circuit the often complex European Union procurement processes but the European Commission has questioned their validity.
The OGC told CW360.com that the original GCat procurement scheme had come under EC scrutiny, but a spokesman would not confirm that the EC was happy with the new agreements.
"We have consulted with EC representatives throughout the procurement and acted on their advice. GCat1 did attract interest from the EC, but there seems to be acceptance that framework agreements are appropriate for IT purchases of this nature," said a spokesman
The new contracts, negotiated by OGCbuying.solutions in collaboration with the NHS Purchasing and Supply Agency, will provide multiple contracts spread over seven categories of IT within GCat 2.
Hugh Barrett, executive director of the OGC supplier relations and e-commerce team, said, "The OGC is delighted to welcome the new arrangements for GCat 2 which represents a significant opening up of the government market to an increased number of suppliers."
Companies were awarded Gcat2 status on the basis of "the most economically advantageous" bids, said the OGC, but there has been some surprise at the limited number of companies chosen.
However, only 154 companies expressed interest in applying for the supplier contracts. The OGC sent out details to 103, of which only 46 responded with just over half receiving Gcat2 status.
Successful companies include Compaq, EDS and UNISYS, while established public-sector IT organisations, such as ITNET and Capita, are not on the list.
The OGC could not confirm if any of the 26 chosen companies were small or medium-sized enterprises.