Nazarbayev's press service confirmed that the changes had been signed into law after a judicial review and parliamentary approval this week.
"The head of state has signed the law 'On amendments and additions to the constitution of Kazakhstan'," the presidential press service said on its Twitter account.
Among the changes is the ability for parliament to hold government members to greater account through votes of no confidence that the president can no longer override.
The government, in turn, will gain an expanded mandate to make and revise policies without checks from the powerful presidency, which will also shed its authority to issue legally binding decrees.
After the death of the strongman Islam Karimov in neighbouring Uzbekistan last year, Nazarbayev is the only living leader in the former Soviet Union that began his rule before the bloc's collapse.
Analysts have said the constitutional changes will mean little as long as the oil-rich country's cabinet and parliament are stuffed with Nazarbayev loyalists.
Last week, a female lawmaker in Nazarbayev's dominant Nur Otan party called for renaming the capital, Astana, and its airport in honour of the 76-year-old leader, who has led the country since 1989.
The declaration set off a flurry of ridicule on social media, but it was not the first time Nazarbayev has refused parliamentary suggestions to give his name to Astana, a glitzy government project that transformed a provincial town into the capital in 1997.
Given his growing personality cult, many feel it is only a matter of time before he concedes to the requests.
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