The World Health Organization (WHO) has expressed alarm about the impact of the UK government’s immigration policy on international academic cooperation after several foreign scholars were denied visas to attend a conference.

The organisers of the Global Symposium on Health Systems Research in Liverpool, which runs until Friday, are compiling a dossier of immigration problems that are understood to have affected at least 10 of the event’s 2,000 registered delegates.

They include Sabu Kochupurackal Ulahannan, who is researching nutrition and inequality among children in remote tribal communities in Kerala, south-west India. He was one of 291 delegates awarded a scholarship to attend the event, in an initiative – partly funded by the UK government – aimed at low- and middle-income countries.

But Kochupurackal Ulahannan, who is studying for a doctorate at Sree Chitra Tirunal Institute for Medical Sciences and Technology in Thiruvananthapuram, the state capital of Kerala, was denied a visa by UK immigration officials. He was told he had an “insufficient balance” on his bank account.

The refusal came after he was was asked to pay 16,000 rupees (£168), equivalent to half his monthly salary, for the visa application. This included a fee to fast-track the paperwork after devastating floods in Kerala meant he could not attend a visa verification interview in Bengaluru until 22 August, six weeks before he intended to travel to Liverpool.

In a blogpost Kochupurackal Ulahannan condemned the actions of the immigration authorities as discriminatory. In an email to the Guardian he added: “It is both racial discrimination and discrimination against [the] poor. My experience shows that people belonging to low income groups from lower and middle countries face double discrimination on the basis of income status and ethnicity.”

Prof Asha George, the chair of Health Systems Global, which is hosting the event, confirmed other academics had faced similar problems.

She said: “We are saddened that some of our colleagues are unable to join us in Liverpool this week for visa reasons. We are committed to finding ways to improve access to forums such as the Global Symposium on Health Systems Research, which promote international debate and exchange on critical global concerns.”

Kochupurackal Ulahannan’s plight has prompted calls for international academic events to be relocated to countries with a less hostile immigration policy.

Dr Masoud Dara, a communicable diseases coordinator at the WHO, said: “International events are better organised in countries where the invited participants can more easily attend. The tough immigration policies may have impact on academic cooperation, if specific measures are not put in place to facilitate scientists’ travel to and from various countries.”

Martin McKee, a professor of European public health at the London School of Hygiene and Tropical Medicine, said it was no longer acceptable for the UK to host international academic events because of visa restrictions.

Martin McKee #FBPE (@martinmckee) It's no longer acceptable to organise major international meetings in UK or US. If you create hostile environments you can't expect people to come & spend money. We had problems during @ASPHERoffice meeting in London - eminent colleague unable to get visa. Disgraceful.

McKee said: “Academic collaboration is yet another consequence of the government’s ‘hostile environment’ policy. At the same time that it is promoting global health through its international development funding, it is denying visas to those who are working on the ground to improve the health of some of the poorest people in the world as they seek to share their experiences and learn from others at conferences in the UK. In these circumstances, it makes sense to hold such conferences in countries where they can participate more easily.”

He pointed out that Prof Vesna Bjegović-Mikanović, a Serbian former president of The Association of Schools of Public Health in the European Region, was prevented from attending the group’s annual directors’ retreat in London in June because of delays to her visa application.

Last month there were warnings that Britain was closing the door on academic collaboration after a Nigerian lawyer was denied entry to attend an African studies conference at Cambridge University.

Kabir Sheikh, the former chair of Health Systems Global, urged members to read Kochupurackal Ulahannan’s blogpost. “The board takes this very seriously and visa access is a key factor among others in host selection,” he tweeted.

In his post Kochupurackal Ulahannan wrote: “The voices of people reporting social injustice and exclusion should emerge from the very communities that face them. However, maintaining a policy of requiring that applicants have a three-month account balance which shows evidence of sufficient means of subsistence, as a crucial criterion for visa approval for conferences on areas of social justice, implicitly implies that a career in those fields is only acceptable for individuals from economically sound backgrounds.”

The Home Office is aware of Kochupurackal Ulahannan’s case, but does not discuss individuals. A spokesman said: “All UK visa applications are considered on their individual merits and in line with UK immigration rules and guidance.

“The onus is on the applicant to demonstrate that they satisfy the immigration rules. In addition to any support provided by a sponsor, decision-makers will take account of an applicant’s own personal and financial circumstances in assessing whether the application meets the requirements of the immigration rules.”