Pack was quoted by the Belgrade-based "Novi Magazin" weekly as saying that she believed that Merkel will tell her hosts in Belgrade that they must have good relations with their neighbours, including Kosovo.
The German MEP called on Serbia to avoid interventions in Kosovo and to develop friendly bilateral relations.
She proposed that the two countries try, through dialogue, to settle technical matters so as to ease the lives of both the Serbs and the Albanians in Kosovo.
As for the Germany-Serbia relations, Pack said that they were good as much as they could be.
German Chancellor Merkel will pay an official visit to Belgrade on Tuesday when she is expected to hold talks with President Boris Tadic, according to a statement from the Serbian president's office.
A day before, on 22 August, Merkel will be in Croatia.