The Irish Family Planning Association (IFPA) revealed 663 counselling sessions were given to women who terminated a pregnancy overseas last year.
The figure accounted for almost half of the 1,504 women, girls and couples who received face-to-face support because of a crisis pregnancy in 2012.
The IFPA said factors for the upsurge in demand for post-abortion counselling included more women attending with complex circumstances.
Its annual report for 2012 also showed:
:: a 6% rise face-to-face crisis pregnancy counselling, up to 1,504;
:: 2,495 callers to the IFPA national pregnancy helpline were supported;
:: 663 post-abortion counselling sessions were provided, up 82%, including new and repeat sessions;
:: migrant women accounted for 16% of clients, up 10%;
:: 3% had a diagnosis of fetal anomaly;
:: 36% of clients attended with a partner/friend/family member or healthcare professional.
Elsewhere it revealed 2,058 men and women were screened for a sexually transmitted infection (STI), up 16% from 2011.
IFPA warned many more people could be carrying infections as those in remote areas do not have access public hospitals, while teens and low income earners struggle to meet the cost of STI screening at private clinic.
Dr Caitriona Henchion, IFPA medical director, said: "The marked increase in numbers attending for STI screening in IFPA clinics last year shows that more people are taking responsibility for their sexual health.
"In order for this positive trend to continue and to support people in looking after their sexual health, adequate and affordable STI screening services must be available nationally."
Most recent figures from health chiefs show STI rates reached a record high in 2011, with a 300% increase since recording began in 1995. Chlamydia, gonorrhoea and genital herpes reached their highest incidence rates, increasing by 19%, 33% and 44% respectively.
Dr Henchion said affordable and comprehensive screening should be available at a primary care level.
"This would ensure that people across Ireland have access to the sexual health services they need," she added.
The IFPA revealed staff also provided almost 17,500 sexual and reproductive medical consultations in 2012, while sexual health training was delivered to 987 students, carers, parents, health workers and community groups, and Dance4life, an international HIV and sexual health education initiative, was delivered to 2,439 students and youth groups nationwide.
The report also highlighted that cervical cancer screening uptake decreases with age, with women over 45 less likely to attend for screening than women under that age.