German Chancellor Angela Merkel threw her weight behind Markus Weber's candidacy for the European presidency at an election rally in Munich on Friday night, on the eve of the EU elections.

Merkel's Christian Democratic Union (CDU) and its Bavarian sister party the Christian Social Union (CSU) were united for their in support of the European People's Party (EPP) candidate.

Weber is hoping the centre-right EPP will become the biggest grouping in the new European Parliament, paving the way to his election as European President.

He was bolstered by speeches from Bavarian Minister President Markus Soeder, EPP President Joseph Daul, former Polish politician Lech Walesa, CDU party leader Annegret Kramp-Karrenbauer, Croatian Prime Minister Andrej Plenkovic, Bulgarian Minister President Boyko Borrisov, Latvian Minister President Krisjanis Karins and German Chancellor Angela Merkel.

Austrian Chancellor Sebastian Kurz was forced to cancel his visit at noon due to the ongoing political crisis in Vienna and instead sent a video message.