The German parliament has already approved the rescue fund, but the president has yet to sign off as part of the ratification process. The court is due to rule Wednesday on a complaint seeking an injunction against the ratification.
Steffen Seibert, a spokesman for Chancellor Angela Merkel, said Monday the government is "convinced" the (EURO)500 billion ($640 billion) European Stability Mechanism is constitutional and expects the court to agree.
A backbench lawmaker with Merkel's conservative bloc has asked the Federal Constitutional Court to delay its ruling in light of a European Central Bank announcement that it would in certain cases purchase government bonds to help financially troubled countries.
But Seibert said the government believes the ECB's move doesn't affect the court ruling.
The proposed bond purchases led the lawmaker, Peter Gauweiler, to file an additional complaint Sunday with the court, which could affect this week's proceedings. The court said it would rule Tuesday on how the additional complaint would affect the proceedings.