There was a 17% increase in the number of sex offenders jailed last year.
New figures also show there are nearly 550 sex-offenders in prison in Ireland at the moment.
According to details released to Newstalk under the Freedom of Information Act, 287 people were jailed for sex-offences in 2018.
This rose to 336 last year - involving 329 men and seven women.
Noeline Blackwell from Dublin Rape Crisis Centre said there are a number of likely factors for the increase.
She said: "The number of complaints and reports being made to the gardaí are rising quarter-on-quarter for the last two and a half or three years, by about 10-15% each quarter.
"As well as that, there has been some additional resourcing of the justice system.
"For instance, the number of protective service units - specialist units of investigation by the gardaí - has risen from four to ten."
At present, there are 544 male sex-offenders in Irish prisons and four women.
29 men, who were convicted of one these offences, have been released from jail so far this year.
A further 147 men are due to be released in the rest of 2020, along with one woman.
