Both the house of representatives and the Senate had passed earlier versions of the bill, and a compromise with the White House had been worked out last month but a small number of Senators were able to block a vote on the bill late yesterday, killing chance of its passage this year.

Under current law, 65,000 H-IB visas are granted annually to non-citizen computer programmers and other highly skilled professionals to work in the United States for up to six years.

The bill would have nearly doubled that to 115,000 for the next two years, and 107,500 in the third year.

After that, the level would drop back to 65,000.

The bill's chief Senate sponsor, Republican, Spencer Abraham, said the decision could hurt the hi-techindustry and academic institutions.

"This is a severe problem and it is especially severe at this time", said Abraham, noting that the industry is trying to resolve the millenium bug issue, when some computer systems may fail if internal clocks do not recognise the year 2000.