The court's move sets the stage for a showdown with Prime Minister Yingluck Shinawatra after she signed the charter amendement Tuesday. It will now be sent to the King for endorsement.
The ruling Pheu Thai Party is also threatening lawsuits against opponents of the charter amendement, as well as against the charter court judges.
The court will consider Wednesday afternoon the petition filed by senators Somjate Boonthanom and Rosana Tositrakul asking the court to issue an injunction against submitting the charter amendement for royal endorsement.
They cited Section 68 of the constitution, claiming the charter changes represent an attempt to overthrow the current democratic system.
The Group of 40 Senators and Democrat MPs on Saturday also submitted a petition opposing the charter amendement to Senate Speaker Nikom Wairatpanich asking him to forward it to the Constitution Court.
Citing Section 154 of the charter, they insisted that Ms Yingluck must delay forwarding the amendement to His Majesty until the charter court rules on its constitutionality.
Prime Minister Office's secretary-general Suranand Vejjajiva said Tuesday the charter amendement is now ready to be submitted to the palace.
Ms Yingluck signed the amendment Tuesday after cabinet secretary-general Ampon Kitti-ampon and Council of State secretary-general Chukiat Rattanachaicharn ran a final check on it.
The change seeks to amend the constitution's provisions governing the composition of the Senate. It would authorise the election of all 200 senators, allowing them to run for consecutive terms, which the current constitution prohibits.
The charter amendement cleared its third and final reading in parliament on Saturday, although it is still subject to several legal challenges in the court.
The cabinet's secretary-general is contacting the Office of His Majesty's Principal Private Secretary to ask it to forward the amendment to His Majesty for royal approval, Mr Suranand said.
He said the Council of State, the government's legal adviser, has made it clear the charter change process was lawful and the prime minister is required to submit it for royal endorsement within 20 days of its passage.
The Council of State said the charter amendement is not covered by Section 154 of the constitution, as claimed by its opponents and referred to a Constitution Court ruling in a similar case on charter change on Feb 23, 2011. The court ruled that Section 154 only covers general bills, not charter changes.
Pheu Thai MP for Chiang Rai Samart Kaewmeechai, who chairs a charter amendment scrutiny committee, said Tuesday Pheu Thai's legal team was looking at legal angles to file lawsuits against those who had tried to block the submission of the amendement for royal endorsement.
Mr Samart said the party will file police complaints against them for malfeasance in violation of Section 157 of the Criminal Code.
He also said that if the court accepted the petition seeking to delay the submission of the charter amendement, the charter court judges could also face legal action for violating Section 157.
Mr Samart said it was actually the court that was trying to pressure parliament and the government, rather than the other way around.
Noppadon Pattama, legal adviser to former prime minister Thaksin Shinawatra, Tuesday urged the charter court to respect the separation of powers between the legislative, executive and judiciary branches. The court is overstepping its authority. It is not a special organisation that can act as it wishes, he said.
Democrat Party leader Abhisit Vejjajiva insisted the charter amendment must be referred to the court.