Asked by mass circulation Bild daily who would take over her Christian Democratic Union (CDU) when she left, Volker Kauder, who leads her conservatives' parliamentary group, said: "We don't need to discuss this question."
"Angela Merkel will again fight an election campaign in 2013 and will then be chancellor for another four years after that campaign is won," added Kauder.
The chancellor swept to a second term in September 2009 at the head of a new-look coalition with the pro-business Free Democrats (FDP) but voters have not warmed to the new team amid internal squabbling on a multitude of issues.
The recent resignation of the most popular member of Merkel's cabinet, Defence Minister Karl-Theodor zu Guttenberg, amid accusations he plagiarised large sections of his doctoral thesis has also damaged her.
Against this backdrop, the opposition centre-left Social Democrats have gained in the polls, hitting 29 percent compared to the conservatives' 33 percent, according to a survey in Sunday newspaper Bild am Sonntag.
Last month the CDU lost power in Hamburg, with their share of the vote almost halving in the first of this year's seven state elections. Two more take place later this month.