Iraqi Defence Minister Khalid al-Obeidi accused the parliament speaker and several lawmakers of corruption on Monday, prompting the prime minister to order an investigation.
The latest parliamentary acrimony came after the legislature was deadlocked for weeks over Prime Minister Haider al-Abadi's efforts to replace the cabinet earlier this year.
And a conflict between Obeidi and speaker Salim al-Juburi -- two of the country's most senior Sunni Arab politicians -- does not bode well for unity in the community ahead of the battle to retake the city of Mosul from the Islamic State group.
Obeidi made the accusations as he appeared in parliament for questioning over corruption allegations brought by Alia Nasayif, a lawmaker whom the defence minister said was herself corrupt.
The session broke down after Obeidi made the accusations, and Juburi then held a press conference denying them.
The meeting of parliament was closed to the press, and while Juburi's denial was broadcast on state television, Obeidi's remarks were not.
But posts on Obeidi's official Facebook page gave a few details on his allegations, including one saying he told parliament that Juburi was "involved in attempting to pass corrupt armament contracts".
Another charged that Juburi and three lawmakers, including Nasayif, sought to blackmail the minister "for the purpose of passing corrupt deals and contracts at the expense of Iraqi blood".
Abadi ordered the anti-corruption commission to investigate the allegations and to cooperate with a parliamentary investigative committee on the issue, his office said in a statement.
"No one is above the law," the statement said.
Following the session, Juburi held a news conference rejecting the accusations against him and the MPs.
"Everything that was raised today is theatre" aimed at allowing Obeidi to avoid questioning by parliament, Juburi said.
Corruption is widespread in Iraq's government, from senior officials to low-level functionaries, and while Iraqis have repeatedly demonstrated for change over the past year, little in the way of real reform has taken place.
The political conflict surrounding the defence minister -- who is from Mosul -- comes as Iraqi forces conduct operations to set the stage for an assault on the city, which has been held by IS group militants since June 2014.