BERLIN — Chancellor Angela Merkel’s opponents defended their plans for tax increases Thursday and dismissed talk of a possible alliance with a hard-left party as polls showed them still trailing badly ahead of Germany’s Sept. 22 election.
Center-left challenger Peer Steinbrueck’s Social Democrats and his allies, the Greens, have struggled to generate any momentum for change against Merkel, a popular conservative.
She has hammered away at her rivals’ plans to increase income taxes for top earners, arguing that the government’s coffers are already in good shape and tax hikes would hurt a healthy economy.
Merkel also is seeking to mobilize supporters by raising the possibility of an alliance between the two center-left parties and the Left Party, which has opposed eurozone bailouts and reform plans and is against German military deployments abroad.
The center-left insists top earners should pay more taxes to help finance education and transportation infrastructure and reduce debts. It says it’s not enough to rely on a strong economy to keep boosting the government’s tax take.
‘‘Too little is being invested in Germany . . . things won’t work without a moderate tax increase,’’ said Winfried Kretschmann, the Green governor of Baden-Wuerttemberg state.