"This is an offer not only for doctors and medical personnel, but for everyone who wants to strengthen the joint capabilities of the civilian medical community and the Polish Armed Forces," he added.
Kosiniak-Kamysz, who is also a deputy prime minister, outlined several ways to take part in the programme.
One option involves completing a five-day military training course, taking an oath of service and joining the army's so-called passive reserve.
Another pathway, aimed at people with university degrees in medicine, includes at least 31 days of military training and the possibility of becoming a reserve officer.
According to the defence ministry, the Medical Legion will also offer opportunities to cooperate on military medicine research and analysis, take part in conferences and workshops, and participate in exercises focused on providing medical aid during conflict, disasters or other crises, Polish state news agency PAP reported.
Participants may also register their willingness to provide medical assistance at home or abroad.
In addition, the ministry promised to offer free specialist courses allowing passive reserve soldiers to gain qualifications in various areas of healthcare.
Kosiniak-Kamysz announced the creation of the Medical Legion in September last year when appointing its leadership.
Officials describe the Medical Legion as a civilian, voluntary platform intended to quickly integrate medical expertise and resources with the needs of the Polish armed forces, including through training programmes, volunteer registration and the creation of regional readiness centres.