The party's board is due to convene for a meeting on Sunday, and 25 members issued a joint statement in favor of Sikkut's candidacy.

Outgoing leader Jevgeni Ossinovski announced he would be stepping down after the March 3 general election, where SDE suffered losses and found itself down to 10 seats (from 14 at the XIII Riigikogu), and out of office.

Riina Sikkut was returned to the Riigikogu at the general election - in fact the first time she had sat in parliament, having been selected from the civil service as Minister for Health and Labor in May 2018.

"Over the past month, we have been involved in various debates on party chairing. To sum up, we could say that we have to choose between experience and freshness on Sunday. Both things have their beneficial and necessary qualities, but freshness is the more important today." the members' statement, circulated internally, read, according to ERR's online Estonian news.

"Freshness, with the courage and determination to stand up for SDE's forward-looking message, is the best thing we can do for ourselves," it continued.

"This is why the choice we are facing is not complicated, but certain: Riina Sikkut is the best candidate as the next SDE chair," the statement added.

"Riina has the combination of freshness, compelling positivity and joyfulness that our party public image needs. She is an experienced and capable analyst, with the ability to convince people in areas important to social democrats. At the same time, choosing Riina as chairman of a political party would not mean concessions in experience," the 25 signatories concluded.

As well as Marju Lauristin, an academic and former MEP, signatories included Toomas Jürgenstein, Triin Toomesaar, Andrei Hvostov, Inara Luigas, Barbi Pilvre, Siim Tuisk, Reet Laja and Kadri Kõusaar.

The two other candidates nominated for the role at present are former culture minister Indrek Saar, and Lauri Läänemets.