The items concern the exercise of judicial power and an increase in parliament seats, respectively. Sixteen more amendments proposed by the ruling Justice and Development (AK) Party will be voted in parliament.
In Tuesday’s first secret ballot, 347 of the assembly’s 550 lawmakers voted in favor while 132 rejected the motion, 66 were absent, two papers were blank, two lawmakers abstained and one vote was invalid.
It changes the ninth article of the Constitution – "the judicial power shall be exercised by independent courts on behalf of the Turkish Nation" – to read "independent and impartial courts".
The second item of the package increases the number of lawmakers from 550 to 600 in accordance with the rising population.
A total of 480 lawmakers took part in the second ballot. It passed with 343 votes in favor, 133 against, one abstention, two blank ballots and one invalid vote. The general assembly session ended after the voting.
The parliamentary process will likely be followed with a referendum in which the option of replacing Turkey’s parliamentary system with a presidential model will be put to the electorate.
President Recep Tayyip Erdogan and his supporters have argued that Turkey needs a strong presidency to avoid weak governance and allow the country to successfully tackle a number of challenges, including terror attacks from Daesh, the PKK and the Fetullah Terrorist Organization. Opponents claim it will weaken democratic checks and lead to increased authoritarianism.
To reach a referendum, the proposed changes must first be passed by 330 deputies. If it gets the support of 367 lawmakers it could pass into law without a referendum, although the ruling AK Party has said it will hold a popular vote regardless.
A simple majority must agree to the changes in a referendum.
The AK Party has 316 seats and Erdogan hopes the support of the opposition Nationalist Movement Party (MHP), which has 39 seats and which last month agreed to back the package, will be enough to secure a referendum.
Parliament’s other parties -- the Republican People's Party (CHP), which has 133 seats, and the Peoples’ Democratic Party (HDP), with 59 deputies -- remain opposed to a presidential system. Two independent deputies are split over support for the amendments.
Among the changes are plans for an elected president to form a government independently of parliament and for the role of prime minister -- typically the person leading the largest parliamentary party -- to be abandoned.
Parliamentary and presidential elections would be held on the same day every five years, instead of the current four for the parliamentary vote.
The president would be limited to two terms of office but will not be required to leave his or her political party. When elected to the presidency in August 2014, Erdogan had to resign as AK Party leader due to the supposedly apolitical nature of the post.
In the judiciary, the Constitutional Court, Turkey’s highest court for constitutional affairs, would be reduced to 15 members while the Supreme Council of Judges and Public Prosecutors, which deals with judicial and prosecution appointments, would add the justice minister to its number.