The Premier League has appointed a firm of corporate investigators to carry out spot-checks and investigations into pubs and clubs showing live matches on Saturday afternoons.
Pubs can access the matches using foreign satellite systems which are often considerably cheaper than the British systems.
The Premier League has now appointed Glasgow-based firm ID Inquiries and will step up the number of pub visits and investigations to a higher level than any previous season.
A Premier League spokesman said: "We look forward to working with ID Inquiries as we significantly up our enforcement activity in this area with more planned investigations than ever before.
"This newly enhanced investigations programme follows recent successes in the High Court, including injunctions against the use of foreign satellite systems, and unauthorised streaming websites, being used in commercial premises to broadcast Premier League football.
"We remind all publicans that Sky Sports and BT Sport are the only authorised broadcasters of live Premier League matches in the UK and that legal action will be taken against those who use unauthorised satellite systems to show Premier League matches in commercial premises."
ID Inquiries has immediately put up a notice on the front page of its website inviting people to report "illegal broadcasts of football matches on commercial premises".
The Premier League is stepping up its measures to protect its rights holders following recent legal successes.
Last week it won a judgement in the High Court requiring the six main UK-based internet service providers (ISPs) to block access to one of the biggest unauthorised live football-streaming sites First Row Sports.