The federal US agency that approves applications for the most sought-after H-1B visas needs to improve upon its current site visit verification program so as to prevent fraud in the visa system, according to a report by the Department of Homeland Security.

US Citizenship and Immigration Services (USCIS), which conducts site visits to companies that hire foreign workers on H-1B visas as part of its objective to detect fraud, "could do more to prevent approving petitions for recurring violations and collaborate more with external stakeholders," said the Office of Inspector General in its latest report released this week.

"The agency lacks performance measures to show how site visits contribute to improving the H-1B Program," the Inspector General said.

Without addressing the challenges, USCIS site visits do not fully safeguard the H-1B Program, and the agency misses opportunities to ensure funds are put to better use through more robust site visits, the inspector general report said.

According to the report, USCIS can approve more than 3,30,000 H-1B petitions each year and, as of April 2017, reported more than 6,80,000 approved and valid H-1B petitions.

"USCIS conducts a limited number of visits and does not always ensure the officers are thorough and comprehensive in their approach," the report said adding that further limiting the site visits' effectiveness, USCIS does not always take proper action when immigration officers identify potential fraud or noncompliance.

It also uses targeted site visits to respond to indicators of fraud; however, the agency does not completely track the costs and analyze the results of these visits, the report said.

As such the inspector general in its report recommends that USCIS Deputy Director, develop a process to collect and analyze complete and accurate data for all H-1B site visit activity.

It also asks USCIS to identify data and assessments obtained through site visit programs post-adjudication and implement measures to systematically share this information with external stakeholders as appropriate.

USCIS has also been recommended to develop comprehensive policies across Directorates to ensure adjudicative action is prioritised on fraudulent or noncompliant immigration benefits identified by the H-1B ASVVP (Administrative Site Visit and Verification Program) and targeted site visits.

Among other things, USCIS has also been asked to enhance the random sampling procedures to also include a more risk-based approach that prioritises the recurring violators within the universe of H-1B holders and a random stratified selection of small.

USCIS has accepted all recommendations.