Train molesters in Japan have a new and disruptive tactic when caught - making an escape by jumping on the tracks.

The phenomenon has been on the increase since March, Japanese paper The Mainichi reported last month.

Running on the tracks is not only dangerous, it often forces trains to temporarily suspend operations, Mainichi said.

There were nine cases in the last two months, Singapore's Chinese daily Lianhe Zaobao said in a report on Monday (May 29).

On April 13, a man in a dark blue jacket shouted "It wasn't me!" before jumping onto the track Ryogoku Station on the Sobu Line, in Tokyo's Sumida Ward, Mainichi reported.

He had just been accused of molestation by two women. The man ran for about 50 metres before climbing over a metallic wire fence.

On May 11, a man accused of molesting a high school girl on a train in downtown Tokyo jumped onto the tracks from a platform at Shimbashi Station and fled.

On May 15, a groper in his 30s, who was being taken away by station staff, jumped into the path of an oncoming train at a station in Aoba and died.

In a few of the cases, trains were delayed for about 20 minutes. For the May 15 fatal incident, trains were stopped for about two hours, a report said.

Those who are caught can be charged with additional offences for disrupting train services.

Being groped on trains is a perennial problem for women in Japan. A survey by a Japanese women's magazine found that the likelihood of being groped on certain train lines was 100 per cent, the Zaobao report said.

Although groping is illegal, many women remain silent as they believe no action will be taken.