NFRN London District president Omkar Patel accused NI of "driving a dictatorial relationship with its newsagents" with terms including a requirement to place a large deposit with NI for the duration of the trading relationship, mandatory weekly payment of account, and charges of 3% above the base rate for late payment.
"All this applies even if the invoice sent to you is massively inaccurate," Patel added.
Exisiting wholesalers take a deposit from new customers which may be returned after the first year, demand weekly settlement, and charge interest of about 1.5% on late payments.
Other retailers praised the clear and concise terms of the document, and pointed out that as NI would deliver only two newspaper titles a day, "massively inaccurate" invoicing was unlikely to occur.
NI said it would deal with individual retailers' queries on its helpline, 0808 238 9599.