The new leader of German chancellor Angela Merkel’s party has said he is confident of securing his colleagues’ support to become the centre-right candidate for the country’s leadership, after a rival also declared his ambitions.

The Union bloc aims to decide quickly on its candidate after months of shadow-boxing between Armin Laschet, the head of Mrs Merkel’s Christian Democratic Union (CDU), and Markus Soeder, who leads its smaller Bavaria-only sister party, the Christian Social Union (CSU).

Mr Laschet and Mr Soeder – the governors of Germany’s two most populous states, North Rhine-Westphalia and Bavaria respectively – both officially declared that they are prepared to run, but insisted that they will quickly find a harmonious solution to the impasse.

The leaderships of the CDU and the CSU are holding separate meetings on Monday.

Asked by the Bild daily whether there is a majority for his candidacy in his party’s leadership, Mr Laschet replied: “I believe so, but we will see (on Monday).”

Mr Laschet’s support in the CDU is a decisive factor because his is by far the bigger of the two parties. It runs in 15 of Germany’s 16 states, while the CSU runs only in Bavaria.

Mr Soeder said he is ready to run “if the CDU — which is the bigger sister, that’s very clear — supports this broadly”.

He added that “it’s also clear that if the big sister says that’s not its proposal and it has a different proposal … we would accept that”.

Mr Soeder said the candidate should be the one with the best chances in the September 26 election, in which Mrs Merkel has declined to seek a fifth term after 16 years in power.

That underlines a weakness for Mr Laschet, as current polls show much better ratings for Mr Soeder, who has cultivated an image as a decisive backer of tough action in the coronavirus pandemic.

Mr Laschet was elected as CDU leader in January but has not enjoyed a honeymoon, most recently garnering criticism for appearing to dither over how to manage a resurgence in virus cases.

Last month, the CDU suffered bad losses in two state elections. National polls have shown the Union giving up gains it made on the strength of Mrs Merkel’s management of the early stages of the coronavirus pandemic.

It has been hurt among other things by a slow start to vaccinations and allegations that several legislators from both CDU and CSU profited from business deals last year as Germany scrambled to secure masks. Some of those legislators have left their parties.

The Union still leads national polls ahead of the environmentalist Greens and the centre-left Social Democrats.

The Greens plan to announce on April 19 which of the party’s two co-leaders will make its first bid for the chancellery. The Social Democrats nominated current finance minister Olaf Scholz months ago.

The CSU has twice provided the centre-right candidate for chancellor in the past – Franz Josef Strauss in 1980 and Edmund Stoiber in 2002. Both lost to centre-left incumbents.