Police then handcuffed the aspiring actress, who has more than 40,000 Instagram followers, and placed her in a paddy wagon.
Images from the arrest show Ms Finlayson being led away by a female officer and Mr Roser escorted to the vehicle in handcuffs by three police officers.
The couple was arrested as part of a major police operation targeting inner-city drug dealing.
Both were charged with 15 offences in relation to the alleged supply of illicit drugs including two charges of supplying prohibited drugs in a commercial quantity.
The alleged offences occurred at Mascot, Waterloo or Zetland over more than a month between April 9 and May 22.
Strike Force Petal was established in December last year to investigate the supply of prohibited drugs, specifically heroin and ice, in the Redfern area.
Police collected evidence from the property as Ms Finlayson and Mr Roser were taken to Redfern Police Station for questioning.
They were charged each with five counts of supply prohibited drug indictable quantity and less than commercial quantity, four counts of supply prohibited drug small quantity and less than indictable quantity, two counts each of supply prohibited drug small quantity, of supply prohibited drugs on an ongoing basis and of supply prohibited drug commercial quantity.
Magistrate Robert Williams formally refused bail for Ms Finlayson who will apply to be released from custody on bail in two weeks' time.
Mr Roser did not apply for bail, which was formally refused by Mr Williams, and was remanded in custody until August 6.
