About $3.9 million of taxpayers' money has been spent investigating, prosecuting and defending the 18 people arrested in the Urewera raids.
The bill is set to rise even higher if a second trial on organised crime charges is sought.
Fresh figures released to the Herald show more than $1.16 million in legal aid has been paid to defence lawyers for the four who stood trial in the High Court at Auckland this year. Just over $93,182 has been claimed for the five-week trial which ended in March.
But the total bill for Tame Iti, Urs Signer, Te Rangikaiwhiria Kemara and Emily Bailey could be higher, as not all the legal aid invoices have been filed to the Ministry of Justice.
The legal aid bill for a fifth defendant, Tuhoe Lambert, was $132,692. He died before the trial started.