SPD representative Björn Böhning confirmed in a parliamentary committee that Diwell worked with McKinsey on an integration plan for refugees, but did not comment on the allegations.
The opposition in Berlin accused SPD and CDU of hindering the investigation into the issue.
"This only confirms the reproach with favoritism that is currently discussed," representative of the German Pirate Party Heiko Herberg said.
The agreement with the consultancy firm has been the subject of discussion for weeks. Diwell who should have been appointed as a new State Secretary for Refugee Matters was eventually rejected and replaced by Ex-Police Chief Dieter Glietsch.
Diwell decided to further consult the government on a voluntary basis, but was later reported to be a part of the McKinsey team and profit from the 238,000-euro contract.
During a recent parliamentary secession, CDU and SPD silenced the issue and actually ignored the criticism of the opposition. Representatives of opposition announced their plans to ask for more information at the plenary session on Thursday and conduct further inquiry into the issue.
