"In countries that have not abolished the death penalty, capital punishment may be imposed only following a trial that complied with fair trial and due process safeguards," Christof Heyns, the United Nations' special rapporteur on extrajudicial, summary or arbitrary executions, said in a release.
The inmates are facing the death penalty after being convicted of being part of a criminal group that engaged in armed robbery of jewelery stores in 2005. They were sentenced to death in Asir in 2009.
Heyns said the crimes, which allegedly were fabricated, would not have been serious enough to warrant the death penalty.
"Any death sentence undertaken in contravention of a government's international obligations is tantamount to an arbitrary execution," Heyns said. "Only full respect for stringent due process guarantees distinguishes capital punishment as possibly permitted under international law from a summary execution, which by definition violates human rights standards."
Juan E. Mendez, the United Nations' special rapporteur on torture, said there are also serious concerns the men were tortured during detention and forced to sign confessions.
"This is not only in breach of Saudi Arabia's international obligations under international law, which imposes an outright prohibition on torture, it is also in breach of the government's international obligation under the Convention against Torture that explicitly forbids the use of all forms of torture for the purpose of extracting confessions or acquiring information," Mendez said.
The seven men were originally scheduled for execution March 5, but a postponement means the sentences could be carried out Wednesday, the United Nations said.