Once the German police had dumped the entire group on Belgian territory, the Belgian border and security police were left to deal with them once again. While the director of the security police granted the group "temporary residence in Belgium" for "humanitarian reasons", he also stressed that this was only "pending negotiation of their repatriation with the Norwegian authorities". The negotiations began on 4 June 1934 and were not concluded until September 1937, when the security police, via the Belgian legation in Copenhagen, wrote a letter directly to foreign ministers Johan Ludwig Mowinckel and Halvdan Koht in a frantic attempt to persuade the Norwegian authorities to recognise the Norwegian Roma's citizenship. The attempt was fruitless: the group could not be regarded as Norwegian citizens.
Both while the negotiations were going on and in the years after the Belgian authorities had to accept this diplomatic defeat, the security police pursued a policy intent on getting Norwegian Roma to leave the country voluntarily. Individuals were regularly subjected to short periods of imprisonment to, in the words of the police, "encourage them to leave the realm". Several Norwegian Roma felt persecuted and harassed to such a degree that they repeatedly left the country for France or the Netherlands. However, bilateral agreements between these neighbouring countries entitled the Dutch and French border police to return Roma without the required residence permits back to Belgium.
The Belgian system of travel warrants, which were implemented by the security police in 1933 as a way of registering and identifying travelling foreign nationals, were also actively used to make conditions for the Norwegian Roma even more difficult. For example, these travel warrants were usually only renewed for one month at a time, which meant that the holders had to regularly apply to the local gendarmerie to have them renewed. Moreover, the travel warrants often contained a clause requiring the holder to leave Belgium by a given date. Combined with frequent controls, provisions like these meant that the travel warrants were often used by the police as a pretext to carry out arrests and impose short terms of imprisonment.
In 1939, family head Karl Modis was arrested and imprisoned after being apprehended with an invalid travel warrant. When he was released later the same year, the security police informed the judge in the case that "Modis belongs to a band of romanichels which we cannot get rid of due to international treaties, and which we are forced to retain in Belgium". Half a year after Modis' release, Belgium was occupied by Germany, and in the autumn of 1943 Karl Modis and several close relatives were subjected to the Nazi extermination policy.