A UN agency has denied firing an employee after the man questioned alleged financial irregularities at its North Korean operations.
The UNDP has been accused of giving money to Pyongyang
Artjon Shkurtaj asked for protection as a whistleblower after losing his job in the United Nations Development Programme (UNDP) in North Korea.
Mr Shkurtaj said he found fake US bills in an office safe and local staff were paid in euros, and not local currency.
The UNDP denied any wrongdoing, and keeping improper accounts.
The agency has been accused by the US administration of handing over cash to the North Korean regime without proper accounting or paperwork, the BBC's Laura Trevelyan said from New York.
The implication is the UN allowed millions of dollars to go to the North Korean government instead of going to programmes to help people in poverty, our correspondent said.
The UN carried out an audit in June and said that while there had been breaches of rules, there had been no systematic diversion of UN money to North Korean authorities.
"UNDP has invited the individual to submit all relevant information to the UNDP office charged with undertaking internal inquiries, but he has so far declined to do so," a spokesman from the agency said.
UN deputy spokeswoman Marie Okabe said the UN Ethics Office was looking into Mr Shkurtaj's appeal for whistleblower status.