Labour MP Andy Slaughter, who represents the Hammersmith district in London where Mr Akbari used to reside, said that authorities in Iran had threatened to destroy Mr Akbari’s body and that he had already been buried, citing information from his family in the UK.
The execution drew strong international condemnation, not only from British Prime Minister Rishi Sunak but also from French President Emmanuel Macron and the EU trading bloc.
Iran has in recent years detained dual national citizens from most western countries, accusing them of espionage, charges widely dismissed outside Iran as being baseless.
Analysts say Iran holds the citizens as hostages to use as leverage against the West, but the policy appears to be backfiring as support to renew a 2015 nuclear deal rapidly ebbs in Europe and North America.
Some Iranian politicians had hoped that the West would renew the deal, which was abandoned by former president Donald Trump, and involved the relaxation of international trade sanctions in exchange for Iran accepting UN inspections of nuclear facilities.
Iranian media announced on Saturday that Mr Akbari had been executed.
In its immediate response to the killing, the UK government sanctioned Iran’s prosecutor general Mohammad Jafar Montazer.
Mr Slaughter said he had “extensive contact for the past few difficult days” with the dual national’s family.
“Earlier today I spoke to Mr Akbari’s daughter in the UK, and she asked me to raise a further distressing matter with the foreign secretary.
“The regime refuses to release Mr Akbari’s body or to allow burial in the place chosen by him, and have made threats to destroy his body unless the family co-operates with their instructions,” he said.
“The cemetery where they were told he should be buried informed the family that burial already took place last week, casting doubt on the time of his execution.
“Will the Foreign Secretary meet with me and the family in the UK, and do what His Majesty’s Government can to ensure that in death, if not in life, Mr Akbari is treated with dignity and respect?”
UK Foreign Secretary James Cleverly responded, saying: “The points that he just raised, I am sure, fill us all with revulsion. We will continue to support the family whatever way we can, and he is absolutely right to call upon the regime to treat Mr Akbari in death with the deference and respect that is legitimate.
“I will follow up on the points he made with our ambassador and communicate our incredible discomfort with the points he has just raised.”
Addressing the execution directly, Mr Cleverly said: “Let there be no doubt, he fell victim to the political vendettas of a vicious regime. His execution was the cowardly and shameful act of a leadership which thinks nothing of using the death penalty as a political tool to silence dissent and settle internal scores.
“Our message to that regime is clear: the world is watching you and you will be held to account, particularly by the brave Iranian people, so many of whom you are oppressing and killing.”
Both the UK Labour opposition party and the ruling Conservative party called to designate Iran’s Islamic Revolutionary Guard Corps as a terrorist organisation, although Mr Cleverly said it was not something that would be discussed at the parliament session.