The NLA, which represents the UK's newspapers, plans to launch the first digital cuttings database - called e-clips - in September.
The service means cuttings agencies will have to subscribe to the NLA's database rather than scan newspapers as before.
Talks between the CIPR and the NLA collapsed last week when the service was officially announced.
'They have announced the service without warning us so we have no confidence that the NLA is treating us honestly,' said CIPR head of PA Francis Ingham.
He said e-clips would enable the NLA to monitor users' searches, and argued that if an article was not convenient for the NLA, it could be censored.
There are further concerns that e-clips will enable the NLA to deal directly with PR agencies and in-house teams, threatening media cuttings specialists.
'We have not agreed that we are happy about how this new service works,' said Romeike MD Les Kelly.
NLA digital managing director Andrew Hughes insisted e-clips would offer a high-quality service, denied costs for cuttings agencies would rise and pledged to honour client confidentiality.
He also denied any intention to deal directly with PR agencies and PROs.
'We are organising an event on 13 July to discuss the system,' said Hughes.