Groups representing police officers in England said they are concerned that their officers could be deployed in Northern Ireland if trouble flares up during the summer.
Police officers from Yorkshire, Northumbria and Strathclyde will take part in training programmes in NI over the next few months.
They will be instructed by the PSNI on how to deal with public disorder.
It is part of an exchange programme between police forces in the UK.
But police federations in Yorkshire say they do not want their officers to become a back-up force for emergencies here.
Bob Pitt is chairman of the South Yorkshire Police Federation.
"Obviously our concern is for PSNI officers in the first instance, they're the ones who are currently facing targeted violence and quite clearly, we've got concerns for our own members on a similar footing.
"It's important for us to separate the proposal as being one of training, as opposed to operational deployment, so whether there's a similar degree of threat that officers would face simply coming across to enjoy the training facilities in NI is a different kettle of fish altogether."
Mr Pitt said the UK's geographical closeness could not be used as a "panacea".
"It can't be something that you can rely on if things flare up in NI and need to be dealt with in the way that the PSNI currently deal with them," he said.
In a statement, the PSNI said:"It is acknowledged that the PSNI have led the way in developing a human rights-based approach to policing and also in negotiating with protest organisers.
"As part of an ongoing process, units from Yorkshire, Strathclyde and Northumbria will be training with PSNI units over the next few months to develop skills, experience and knowledge.
"In turn, PSNI officers will assist colleagues in Northumbria and Strathclyde in policing potential public order situations."