Austria's Chancellor Karl Nehammer promised to avoid making secret side agreements in future coalitions.

"With me, there will be no secret agreements outside the government program in future governments," the head of government and Austrian People's Party (ÖVP) leader told the Kronen Zeitung newspaper on Wednesday.

He said he stood by the agreements on appointments to posts, but that they had to be made public and transparent. "It must be clear to everyone that secret agreements damage trust in politics."

Recently, so-called "side letters" from the time of the 2017-19 ÖVP coalition with the far-right Freedom party of Austria (FPÖ) and the current alliance (since 2020) between the ÖVP and the Greens have come to light.

These were co-written by the former chancellor Sebastian Kurz, and included appointments to positions such as the high courts, the National Bank or at the European Union level.

They also contained commitments on policy goals, such as the headscarf ban for female teachers, which the ÖVP wanted but which did not appear in the official coalition agreement signed with the Greens.

The publication of that side letter caused unrest and embarrassment among the Greens, who have always been keen to promote transparency.

The party and parliamentary group leadership denied making the secret commitment, with the party leader Sigrid Maurer claiming it was in any case irrelevant, as a ban on headscarves was bound to fall foul of Austria's Constitutional Court.

The side agreements also included numerous personnel matters at the public broadcaster ORF.

Former ORF director Alexander Wrabetz confirmed that such agreements had been implemented under the former coalition between the ÖVP and FPÖ.

The parliamentary ÖVP corruption investigation committee is to look at possible post-fixing and abuse of power. It starts work on March 2 with the questioning of Chancellor Nehammer.