An Australian Federal Police (AFP) staffer and former Russian soldier will not have to spend any further time in jail after pleading guilty in the ACT Magistrates Court to stalking his former partner.

Roman Eiginson, 53, spent about five months in jail before pleading guilty to stalking and illegally accessing police information.

He used the information to target his former girlfriend last year.

The court heard the couple split after the victim returned from overseas to find Eiginson had married a Russian woman while she was away.

But when the victim found another partner, Eiginson illegally accessed the police database to get information about the pair and for five weeks stalked the woman in person, by email, mobile phone and on Facebook.

He also hung around outside her home where she lived with her new partner, and at one point accosted her as she arrived at her workplace.

Eiginson, a former Russian soldier, had joined the AFP as a staff member in the counter-terrorism unit after moving to Australia.

He has been suspended from his position.

Eiginson was sentenced to around five months' jail, but has been released for time served.