The new basic law, approved by referendum in March, creates a new post of vice-president and requires the holding of a snap election in August to a new, smaller parliament.
"We intend to carry out a major overhaul of the foundation of Kazakh statehood, the foundation and load-bearing structures of the country's independence," Tokayev, who is limited to a single term that expires in 2029, told parliament on Tuesday.
Kazakhstan's status as a major oil producer and exporter makes it the most important economic player in Central Asia, which was part of the Soviet Union until 1991. Since independence, it has fostered warm ties with Russia, the West and China.
The constitution was drafted and approved in a matter of weeks this year, sparking widespread speculation about Tokayev's political future.
Whoever becomes vice-president will be first in line to succeed the former diplomat and United Nations official, who took office in 2019 as the handpicked successor of Kazakhstan's founding president, Nursultan Nazarbayev.
The new constitution represents "a new mechanism for handing over power from the second president to the third", political analyst Rustam Burnashev told Reuters.
Though Tokayev has broadly retained Nazarbayev's authoritarian system, their relationship broke down in 2022, after a bout of nationwide unrest killed hundreds. Tokayev called it a coup bid by a faction loyal to his predecessor.
