ANC leader Musalia Mudavadi has demanded the resignation of suspects named in the Sh8billiion NYS scam.
It is alleged that senior government officials used proxies to register companies that were used to syphon money from the service.
Several officers including the PS Lillian Omollo and the director general Richard Ndubai have recorded statements.
They have also provided the DCI with procurement, finance and accounting documents dating back to 2011.
"All the officers around this issue must immediately step down to allow full investigation into the matter," Mudavadi said.
In a statement to media houses on Wednesday, Mudavadi said the officers should step down within 24 hours.
"Reprobates must be charged in court and due justice brought to them. If they do not resign within the next 24 hours, president Uhuru Kenyatta must demonstrate that he means business. He must remove them at once," he said.
Terming the heist as heartbreaking, Mudavadi said the scandal speaks of blatant, planned and deftly executed theft of public funds by people who should be custodians of public interest.
"The scenario reads like one where the funds were from the outset budgeted to be stolen. They were then released with clear agents eagerly waiting downstream to execute the final phase of the wicked plan," he said.
Mudavadi said Cabinet Secretary for Finance (Henry Rotich), the Controller of Budget (Agnes Odhiambo) and the Cabinet Secretary for Devolution (Wamalwa Eugene) owe Kenyans an explanation.
"They must jointly and severally be held responsible for this act that can only be described as a robbery. Dry-eyed impunity does not get worse than this," he said.
On Monday, the National Youth Service refuted claims that Sh8billion was lost in a new scandal.
PS Omollo disputed a report by the director general of the National Intelligence Service that 13 vouchers amounting to Sh8b were paid to "ghost" companies for non-existent supplies to the NYS.
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