US lawmakers and experts on Wednesday expressed concern over the dramatic increase in request for evidence for H-1B visa applications for foreign workers, of which Indian professionals are major beneficiary.

"The tech economy in Toronto is growing faster than the tech economy in Silicon Valley and Washington. A lot of people think it's because of USCIS and our immigration policies," Congresswoman Susan Ellen Lofgren said on Wednesday during a congressional hearing on Citizenship and Immigration Policy Changes and Processing Delays.

Spikes in unnecessary Requests for Evidence (RFEs) from the agency that freeze case processing and drain adjudication resources, said Marketa Lindt, president, American Immigration Lawyers Association.

In the first quarter of 2019, US Citizenship and Immigration Services issued RFEs in response to 60 per cent of H-1B petitions, dramatically higher than the 20.8 percent H-1B RFE rate in fiscal 2016.

"Often these RFEs seek irrelevant or previously furnished information, or reflect sub-regulatory policy changes or heightened legal standards that the agency has implemented without a change in statute or regulation and of which the agency failed to provide adequate" notice to the public," Lindt said.

Lofgren asked USCIS Service Center Operations Associate Director Donald Neufeld about such a high number of RFEs for H-1B visas in the last one year.

According to the USCIS official. this is mainly due to the number of changes that have been made.

"When there's a change that is introduced, we have to first we train our folks, but we also have to educate the public on what the requirements are," he said. "So whenever that happens... it's pretty predictable that we will have an increase in request for evidence perhaps an increase in denials," the official said.

"Usually over time as the public becomes familiar with what the requirements are and as our adjudicators become more proficient, then we usually will see that the request are the impact of those changes do become more stable," Neufeld said.

Lindt said that sudden jump in RFEs for H-1B visas was particularly confounding.

The key impact is that it's making, from the employer side, very, very difficult to plan, she noted.

"The RFEs are especially exacerbating that because it adds a whole level of uncertainty, both in terms of timeframe and in terms of outcome, to staffing these important positions,” Lindt said.