Alexander and Monica Klein from Malmö were among the first to go through one of the 34 checkpoints that have been set up at Copenhagen airport's Kastrup train station.
“There were no problems. I knew about this so I just had to show my driving licence,” Alexander Klein told the TT newswire.
A total of 150 security staff have been stationed at the airport to oversee the controls. Under the new rules, rail commuters have to exit the train at the airport and go through checkpoints before boarding the train again in order to travel onwards to Sweden. Those without valid ID are refused entry.
It is the first time in half a century that Sweden is demanding photo identification for all travellers from Denmark and deals a blow to Europe's cherished passport-free Schengen system. Only passports, driving licences and Swedish national identity cards will be accepted by the authorities.
The measures are aimed at keeping out undocumented refugees and come after Sweden, which has taken in more asylum seekers per capita than any other European nation, said it could no longer cope with the unregulated flow of new arrivals.
Had your ID checked to travel between Denmark and Sweden? How did it affect your commute? #idkontroller #Öresund pic.twitter.com/wCn2RRXhOj
— The Local Sweden (@TheLocalSweden) January 4, 2016
Travellers were warned they could face delays of more than half an hour during rush hour. The journey between Malmö and Copenhagen's main train stations normally takes no more than 40 minutes.
“I won't manage this for very long. I will have to look for another job,” Helena Sjölander, who lives in Malmö but works in Copenhagen, told the regional Sydsvenskan newspaper as she embarked on her journey.
Hedin Argavan, another traveller, told Swedish daily Dagens Nyheter that she had watched the doors to her planned train close after getting delayed by the checks and was forced to wait for the next one on a freezing platform.
Alexander and Monica Klein who were the first Swedes to have their ID checked when the new control came in. Photo: Johan Nilsson/TT
Well, that was that. Now en-route to the city centre. No problems, if anything quieter than usual #öresund
— Nicholas Bean (@nickobeano) January 4, 2016
Kastrup airport station, where a fence has been put up to stop anyone running across the tracks. Photo: Johan Nilsson/TT
Swedish Migration Minister Morgan Johansson also defended his country's systematic controls, saying they were aimed at “preventing an acute situation where we can no longer welcome asylum seekers properly”.
The Öresund bridge which links Sweden and Denmark. Photo: Johan Nilsson/TT