'Quieter' Sydney morning after 3.2 million tune into Socceroos match

More than 3 million tuned in to watch the Socceroos play Denmark on Thursday night which could have contributed to traffic being "noticeably lighter" on Friday morning.

The Sydney Harbour Bridge was lit up green and gold for the Socceroos match against Denmark. Source: SBS News

Sydney commuter numbers were "noticeably lighter" on Friday morning - and the World Cup could be to blame.

While there were issues on several train lines, commuter numbers on the city's roads and rail were certainly "soft", a Transport Management Centre spokesman told AAP.

Fridays are usually busier and authorities are now wondering if soccer fans were up late watching Australia vs Denmark and other Round One matches from Russia.

The match was the most watched program of the night, attracting 3.2 million viewers in Australia. 

An average of 2.1 million viewers watched the live broadcast on SBS of the tight match in Samara. 

The broadcast is the 13th highest-rating free-to-air program nationally in 2018 to date.