A man has admitted demanding $1300 from a user of mobile phone gay dating app Grindr in return for not telling the victim’s girlfriend.

Timothy Ruge, 34, appeared in Melbourne Magistrates Court on Wednesday, where he pleaded guilty to making an unwarranted demand for money with menaces.

Court documents allege the victim was using Grindr ‘‘to chat and flirt’’ on March 2 this year when he selected Ruge’s profile.

Ruge allegedly responded with an image of the face of the victim’s fiancee, commenting: ‘‘She’s pretty, you cheating bastard’’.