Pasztor told the press it was necessary to defuse tensions and that Vojvodina's autonomy must not be the subject of political sniping.
He said he decided to postpone the session after consultations with the parliamentary groups of the ruling majority and in agreement with Pajtic.
The ruling Serbian People's Party, the Socialist Party of Serbia and nationalist Serbian organisations object to the adoption of the declaration, saying it will lead to Vojvodina's separation from Serbia.
Pajtic dismissed the accusations that the declaration was destabilising Serbia, saying Vojvodina's residents were devoted to Serbia and that nothing could change that.
He previously said the declaration should be adopted because acquired rights were being undermined in Vojvodina. He said the declaration would stress "that failure to respect the principles of autonomy and constitutional and legal solutions weakens the rule of law and European democratic practice, thereby jeopardising the stability and normal functioning of a responsible state."