Registrar of the Supreme Court said the five-judge bench would give their decision to the president and speaker of parliament within 24 hours.
On Monday, the cabinet approved a proposal to scrap the two-term limit for presidents, which would enable Rajapakse to strengthen his grip on power by standing again in November 2016.
Rajapakse came to power in 2005 and won a second presidential term in January, propelled by the victory of government forces over the Tamil Tiger rebels last May, which ended 37 years of bloodshed.
Critics and human rights groups accuse him and his family members, who hold key positions in government, of ruling the Indian Ocean island with an iron fist, crushing dissent and the opposition media.
The government information department said the Supreme Court decision would be announced in parliament for a debate on Wednesday, with a final vote expected on Thursday.
Rajapakse has enough support in parliament to secure the two-thirds majority required to pass