German business leaders have warned that the country's next government must maintain political stability and strive to remain competitive, as pressure mounts on Chancellor Angela Merkel ahead of elections on September 22.

The comments come as the controversial issue of Greece resurfaced with a vengeance this weekend, after Merkel insisted the country would not need a debt write down. The topic – which is hugely unpopular with German voters – could be having an impact on Merkel's campaign for a third term in office after a poll released on Sunday showed that her center-right coalition had lost its slight lead over parties on the left.