The European Commission (EC) has granted Oracle extra time to respond to its anti-trust concerns over the $7.4bn acquisition of Sun Microsystems.

"Oracle requested the extension in order to have the opportunity to develop its arguments," according to the EC.

The EC's concerns are listed as a Statement of Objections issued on 9 November. Oracle was requested to respond to the objections by 19 January, but has now been given until 27 January.

The main objection is that Oracle, the largest proprietary database vendor, is buying Sun, the owner of MySQL, the most popular open-source database in the market.

Oracle has argued that it will not threaten competition because its own database products are aimed at a different type of customer to Sun's.

However, many commentators are urging Oracle to agree to sell MySQL to a third party so that the deal can finally be approved.

Sun desperately needs the deal to go through as it continues to lose revenue to rivals IBM and HP.

Sun's customers have also been left in a state of uncertainty over Oracle's plans for the open-source firm’s product development.

Oracle's critics now argue that the extension period is a sign of Oracle backtracking on its previous remarks that the EC's actions are unlikely to harm its acquisition procedure.

"If the EU's objections were baseless, Oracle would not need more time to develop its arguments," said Florian Mueller, a MySQL shareholder who has long opposed Oracle's plans to acquire the open source database.

"One more week will not change the fact that MySQL competes fiercely with Oracle's database products including its flagship 11g across all major markets.

"The best way Oracle can make use of this extra week is to think really hard about selling MySQL to a suitable third party."