TURIN, Italy (AFP) -- Popular Rome mayor Walter Veltroni is expected to announce later on Wednesday that he will join the race to lead Italy's nascent Democratic Party.

Ahead of his highly-anticipated speech in the northern industrial city of Turin, Italian newspapers devoted headlines to what they had dubbed 'Veltroni Day'. The new Democratic Party will see the merger of former communists and Christian Democrats and will be formally created in October. With polls predicting that support for the party would surge if Veltroni, 51, headed it, the governing center-left is also pinning its hopes on the new party. Public support for Prime Minister Romano Prodi and his coalition that ranges from communists to Christian Democrats has slumped dramatically after just over a year in power. If successful, the merger of the Democrats of the Left and the centrists and Christian Democrats of the Margherita (Daisy) would create a party larger than former prime minister Silvio Berlusconi's Forza Italia and possibly a cure for Italy's chronic political instability. Veltroni, a former communist-turned-social democrat, is due to deliver his speech at 1500 GMT, to be shown live on several television channels as well as on giant screens outside the building. Turin, home to the Fiat car maker, has been chosen in a bid to reconquer territory lost to the center-right in the wealthy north in local elections earlier this month