One in seven candidates for next week's parliamentary elections have been booked for election-related offenses, prosecutors said Wednesday.

A total of 133 of 944 candidates registered to compete for the April 13 polls, or 14.1 percent, have been booked for charges related to irregular election campaign activities, according to the Supreme Prosecutors' Office.

Of the 133 candidates booked for allegedly violating the Public Official Election Act, 125 are being investigated, SPO officials said.

Some 45.9 percent, or 61 people, have been caught for negative campaigning, followed by bribery with 22.6 percent, and spreading lies about rivals with 6.7 percent, according to the SPO.

State prosecutors said the number of election-related offenders has also increased in the lead-up to the poll, compared with the previous general election four years ago.

A total of 938 people had been cited for conducting irregular election campaign activities as of Monday, compared with 726 during the same period in the 2012 parliamentary election.

The prosecution has vowed to take stern measures against all election law violations and stressed to mobilize all possible forces against three major election-related offenses.

The three are giving bribes, using unauthorized methods to sway votes and spreading lies about rivals. (Yonhap)