Ad hoc prosecutor Datuk V. Sithambaram applied for the trial to continue on Monday (April 22) instead, as both sides have a prior engagement on Friday (April 19).
Attorney General Tommy Thomas said his team has to attend a meeting over the "proposed separation of powers of the prosecution's office and the Attorney-General's Chambers".
The defence team lead by Tan Sri Muhammad Shafee Abdullah agreed to the postponement.
Justice Mohd Nazlan Mohd Ghazali allowed the sixth day of proceedings to be postponed to April 22, though he ordered for the afternoon proceeding to continue on Thursday (April 18).
Before the prosecution could call its sixth witness ABS Trendmaster Sdn Bhd interior designer Zulkarnain Mohd, 46, to the stand, the defence objected, arguing that he was an irrelevant witness.
Earlier Thursday, the fourth witness - AmBank cheque processing centre senior manager Badrul Hisham Mohamad, 42 - revealed that accounts believed to be linked to Najib had issued millions in cheques to various parties.
One cheque, worth RM100,000 was issued to ABS Trendmaster on Feb 12, 2015.
Defence counsel Farhan Read argued that the witness did not have relevance as the nature of the charge under the Anti-Money Laundering, Anti-Terrorism Financing and Proceeds of Unlawful Activities Act 2001 is specific to receiving of illicit moneys and not how it is spent.
"I propose to enquire with the prosecution why this witness is being called. We are not as advantaged as the prosecution, we can only guess what the prosecution intends to bring up," he said.
He added that the Attorney General could use these witnesses to "stand on his soapbox and tell whatever for media fodder or propaganda".
Thomas argued that if the objection is allowed, the defence can question every time they think evidence might be troublesome.
"How can the court decide whether we can or cannot call a witness? It creates an extraordinary situation where we would be stymied from proving our case," he said.
Justice Nazlan ruled that the spending is relevant to the seven charges, and allowed the witness to be called.
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