Rajapakse, who oversaw the defeat of the Tamil Tiger rebels last year after decades of civil war, has a firm grip on power in Sri Lanka and has been criticised for crushing dissent and opposition media.
He looks set to gain the two-thirds majority among lawmakers needed to pass the proposed law, which will end the current two-term limit on presidents.
Rajapakse won a second term in January but would have to step down in 2016 under the present constitution.
"The Supreme Court has said the Constitutional Reforms Bill does not require a referendum in order to be passed, instead it only requires a two-thirds majority in parliament," Speaker Chamal Rajapakse, who is the president's elder brother, told lawmakers.
The draft bill will be debated and voted on by the 225-member parliament on Wednesday.
Rajapakse's cabinet approved the proposed constitutional amendments last week.
Rajapakse came to power in 2005 and won his second presidential term on the back of the defeat