Around 10,000 have been expected to take part in the event, which will be staged in Belfast between 1- 10 August.
Athletes from 54 countries have signed up for the World Police and Fire Games (WPFG), with 4,348 registered and a further 2,706 in the pipeline.
Chief Executive John Tully said he is confident organisers will find another 3,000 participants to meet their target.
"We tend to find from our discussions with the federation who have been running these games since about 1985, that the athletes that are closer to the host city for the games tend to leave their registrations until later in the schedule.
He added: "We will be accepting those registrations right up until August, when the games start."
Belfast Lord Mayor, Alderman Gavin Robinson, said excitement across the city and beyond is really building.
"Our city is looking forward to showcasing all that it has to offer and to extending the hospitality and welcome for which we have become famous worldwide.
"Our venues across Belfast are gearing up to host what is one of the largest global sporting events. This is a wonderful opportunity for visitors to experience our world class facilities, and I am delighted that the economic benefits for Belfast and further afield will be enormous."
The games will cost around £7m and are expected to generate £15m into the local economy, with an estimated 15,000 visitors coming to Northern Ireland from 70 countries.