Such a "background agreement" could be announced this week, and the agreement might be an "unpleasant surprise" for Europe, Orban was quoted by the Hungarian ATV as saying.
Pressure on Budapest from the EU authority to accept additional refugees is expected to be significant but is something Hungary will not accept, the prime minister added.
On Sunday, the European Commission held a joint summit with Turkey. The primary issues on the agenda were Turkey's prospective EU membership and the ongoing refugee crisis.
Following the meeting, a deal was agreed upon, under which Turkey promised to prevent refugees currently in the country from traveling to Europe in return for cash and renewed talks on its accession to the European Union.
Hungary's ruling party, Fidesz, headed by Orban, is known for tough stance on immigration.
Amid the ongoing migrant crisis in Europe, Hungary, used by hundreds of thousands of migrants as a gateway to wealthier EU member states, built a fence on its border with Serbia, and reinstated border control measures.