The group, representing health care workers, university professors and religious groups, among others, argued in federal court in San Francisco that the new fee is illegal and will thwart a key conduit for innovation and economic growth in the United States.

"Without relief, hospitals will lose medical staff, churches will lose pastors, classrooms will lose teachers, and industries across the country risk losing key innovators," the coalition said in a statement.

"The suit asks the court to immediately block the order and restore predictability for employers and workers," it added.

The $100,000 fee announced last month gave companies just 36 hours notice before it went into effect, triggering chaos and confusion over how it would work and who would be hit.

The H-1B fee is part of a larger crackdown by President Donald Trump, who has unleashed a massive push against immigration since returning to the White House -- though until now it had not targeted the visa on which Silicon Valley relies heavily.

Trump argued that the H-1B visa system was being abused to replace American workers with people willing to work for less money.

The United States awards 85,000 H-1B visas per year on a lottery system. India accounts for around three-quarters of the recipients.

Tech entrepreneurs -- including Trump's former ally Elon Musk -- have warned against targeting H-1B visas, saying that the United States does not have enough homegrown talent to fill important tech sector job vacancies.