An interim final rule was released by the Department of Homeland Security (DHS), a system for determining the employment eligibility of new hires, giving the extension that will be available to students under F-1 visa who have a degree in science, technology, engineering or mathematics and are employed by businesses enrolled in the E-Verify programme.

"This rule will enable businesses to attract and retain highly skilled foreign workers, giving US companies a competitive advantage in the world economy," said Michael Chertoff, Homeland Security Secretary.

"By extending the training period by an additional 17 months to students who are employed by businesses enrolled in E-Verify, we are further ensuring a legal workforce in the US," he added.

Top tech companies have been extensively lobbying Capitol Hill to substantially increase the numbers of the H1B visas, now pegged at 65,000.

Under the Optional Practical Training students are eligible for up to 12 months of training after completion of their course requirements.