David-Hillel Ruben, a former director of New York University in London, has met with the University and College Union to encourage it to represent staff at US study-abroad sites in the capital.
Professor Ruben estimates that about 22,000 students a year attend US study-abroad sites in London, with teaching and administrative staff "normally" being British.
But as the UCU does not have any recognition agreements with US institutions, it cannot collectively represent staff.
There are 118 members and affiliate members in the Association of American Study Abroad Programmes UK, including major institutions such as Yale University, the University of Notre Dame and Florida State University. Also established in the capital are US for-profits such as the American Institute for Foreign Studies.
"Study abroad is a very profitable business. The (tuition) cost to the American students here is not less than what it would be back in America," said Professor Ruben, currently a philosophy lecturer at Birkbeck College, University of London.
However, staff pay and conditions are generally inferior to those offered at US home campuses, he said.
Professor Ruben said that conditions vary across the campuses, but US parent institutions often "import top-down, non-consultative US managerial practices into their dealings with the UK staff who run their UK operations and teach at them".
"Even when they are technically legally compliant...concerning terms and conditions of employment, there is no one to help staff improve what is on offer from them."
Although Professor Ruben offered no estimate of the total number of staff at US study-abroad sites in the capital, he noted that NYU London alone employs about 80 staff.
Some institutions lack a formal pay structure, he said.
"If enough staff join [a union], US study-abroad institutions in the UK can be forced to recognise the union as representing staff, so...employers will be forced to consult and negotiate with the union as a collective bargaining agent rather than with staff on a one-to-one basis, with all the potential threatening behaviour and intimidation that sometimes comes with that modus operandi."
A spokesman for Notre Dame, the only university to respond to queries, said students in its international studies programmes "pay the same tuition as students on our home campus. In consultation with outside experts over the years, we have ensured that our total compensation package is positioned competitively within the markets (where) we compete for talent and that our employment practices are consistent with the local market."