Undercover staff will ride on Greater Manchester's trams in bid to stop "inconsiderate and ignorant behaviour".
Current bye-laws prohibit swearing, smoking, being drunk and littering.
The stricter approach, which begins in January, will see people breaking the bye-laws being "far more likely" to face prosecution, Transport for Greater Manchester (TfGM) said.
TfGM said 520 breaches were reported between 15 July 2017 and 21 July 2018 but no prosecutions were brought.
The laws already allow for both a potential prosecution and a fine of up to £1,000.
'Message is clear'
A TfGM spokeswoman said Metrolink staff were being trained to collect evidence in accordance with the Police and Criminal Evidence Act (PACE) and would be deployed from 1 January on the network "both in uniform and plain clothes".
She said the PACE training could also mean offenders being formally cautioned.
Criminal behaviour, such as violence or theft, would continue to be dealt with in conjunction with Greater Manchester Police, she said.
TfGM's head of Metrolink, Danny Vaughn, said the message to people breaking bye-laws was that "there will be consequences for their actions".
"It is unacceptable that people should have their journey experience on Metrolink spoiled by the inconsiderate and ignorant behaviour of others," he said.
"The bye-laws exist to prevent this from happening so our message is clear - from January you are far more likely to be prosecuted and fined if you choose to ignore or flaunt them."
The new approach will be proceeded by a two-month campaign, reminding passengers of the network's bye-laws.