The victory of Germany's Social Democrats and the election of the country's first openly transgender lawmakers has buoyed LGBT+ activists' hopes for gains on trans rights after scant progress during Angela Merkel's 16 years as chancellor.

Two Greens party candidates, Tessa Ganserer and Nyke Slawik, made history by winning Bundestag seats in Sunday's election as provisional results showed the center-left Social Democrats (SPD) had narrowly won over Merkel's conservatives.

"At a time when people still make fun of us, when some trans people still face (bullying) or lose their jobs, this is historic," said Slawik, 27, from the western city of Leverkusen.