As Germany's lower house of parliament prepares to debate debt reform, questions are being raised about whether the outgoing Bundestag has the authority to make such decisions.

The Left Party and the far-right Alternative for Germany (AfD) have filed lawsuits with the Constitutional Court to block the special sessions this week and next. They argue that such moves are a violation of the rights of the new members of parliament.

Following elections on February 23, which saw the conservatives come out on top, the old Bundestag continues its work until the new parliament convenes for the first time on March 25.

The debt reform requires a two-thirds majority to change Germany's constitution. But electoral gains by the AfD and The Left last month mean it could be much harder to win support once newly elected lawmakers take their seats.

Instead, the CDU/CSU, led by Friedrich Merz, and the SPD are hoping to push the plan through the outgoing parliament with the help of the Greens. Until the new Bundestag convenes, the old parliament is considered to have a quorum and the authority to make decisions.