An MP accused the government of trying to share a "best practice of how to behead" with Saudi Arabia after the Justice Secretary defended the Government's attempt to sell expertise to the country's prison service.
Shadow justice secretary Sadiq Khan slammed the MoJ bid for the £5.9 million contract.
Justice Secretary Chris Grayling defended the move, saying the Government has always tried to encourage "improvements" and "best practice" in countries around the world.
The pair clashed after reports that the MoJ's commercial arm, Just Solutions international, is hoping to sell its expertise to Saudi Arabia's prison service.
Government cuts could be behind half of convicted sex attackers, violent criminals and burglars avoiding prison sentences, Labour said.
Ministers have been accused of insulting victims after it emerged that half of convicted sex attackers, violent criminals and burglars are avoiding prison sentences.
Thousands of serious criminals have walked free from court, including 46% of paedophiles who abused children aged under the age of 13.
Some 49% of those convicted of sexual assault in 2012 - 2,324 offenders - did not receive a custodial sentence, and nor did many burglars and drug dealers.
Shadow justice secretary Sadiq Khan, who used parliamentary questions to obtain the statistics, said Government cuts were undermining the system.
"This will be an insult to many victims of crime who want to see those who committed crimes against them properly punished and rehabilitated," he told the Daily Telegraph.
Labour's shadow justice secretary Sadiq Khan has described the government's prison reforms as "tinkering around the edges" of the problem.
Khan told Daybreak that it should be investing in more women's treatment centres and more smaller prisons. He said in an earlier statement: "With only a small number of scattered women’s prisons, the concept of local resettlement is almost meaningless."
Labour have reportedly drawn up plans to lower the voting age from 18 to 16 in an attempt to capture more support.
The Sunday Times said Labour's shadow minister for London, Sadiq Khan, had prepared the key reform, which could be introduced for the 2020 election if the party return to power in 2015.
Labour's shadow justice secretary Sadiq Khan has suggested that the coalition should bar G4S and Serco from bidding for future government contracts, including a tender to run the probation service.
He also called for both the police and Serious Fraud Office to investigate all of the contracts that both companies currently hold with government departments.
Shadow justice secretary Sadiq Khan said David Cameron has "failed to deliver" on prisoner rehabilitation, he added that the coalition has "wasted the last three years doing nothing".
He said: "The Government has no idea how their policies will be implemented.
"They have no answers to questions such as how much will the doubling of the workload for probation cost, where the money is coming from or how the overcrowded prison estate cope with their local resettlement plans."
"This is another wasted chance by the Government - it should have pursued a model that focused on evidence of what works to reduce re-offending.
"Instead it has obsessively pursued pet projects leading to the imposition of an untried and untested payment by results model on the probation service which will take big risks with public safety and taxpayers' money."