On the eve of the Bundestag vote, Armenian President Serge Sarkissian told Bild daily: "It would not be fair to not call the genocide of Armenians genocide just because that makes the head of state of another country angry."
"I am sure that Bundestag politicians see it this way too and will not be intimidated," he added.
In Ankara, Turkish Prime Minister Binali Yildirim stepped up pressure against the vote, calling it "absurd", and warned of consequences for ties with Germany if the resolution were passed.
Yildirim's call adds to a similar warning by Turkish President Recep Tayyip Erdogan, who also telephoned Chancellor Angela Merkel on Tuesday over the resolution.
Put forward by Germany's ruling left-right coalition and the opposition Greens, the resolution entitled "Remembrance and commemoration of the genocide of Armenians and other Christian minorities in 1915 and 1916" also carries the contested word throughout the text.
Turkey and Armenia have long been at loggerheads over the World War I-era massacre.
Armenians say up to 1.5 million of their kin were killed between 1915 and 1917 as the Ottoman Empire was falling apart but modern Turkey rejects the claim.
Ankara argues that 300,000 to 500,000 Armenians and as many Turks died in civil strife when Armenians rose up against their Ottoman rulers.
Warning of a "negative impact" on ties between Ankara and Berlin if the resolution is passed, Turkey's prime minister said: "The text has no value for us. It will be null and void."
"It's an absurd vote. History should be left to the historians," Yildirim told journalists in Ankara.
The vote comes at a particularly awkward time, as Germany and the European Union need Ankara to help stem a migrant influx even as tensions are rising over a string of issues, including human rights.
The issue is also particularly sensitive in Germany, as it has special ties with Ankara not least due to its three-million-strong ethnic Turkish population which settled following a massive "guest worker" programme in the 1960s and 1970s.
More than 20 nations, including France and Russia, have recognised the Armenian genocide.