Russian President Dmitry Medvedev sent “heartfelt congratulations” to Nazarbayev after the official election commission declared him the winner on an 89.9 per cent turnout.
But observers from the Organisation for Security and Cooperation in Europe (OSCE) claimed to have witnessed ballot box-stuffing and pressure from officials on voters to go to the polls.
The “needed reforms for holding genuine democratic elections still have to materialise as this election revealed shortcomings similar to those in previous elections," an OSCE statement said.
One of Nazarbayev’s three official opponents, environmentalist Mels Yeleusizov, said he had "expressed my respect for the winner" by voting for Nazarbayev.
The main opposition parties called for a boycott of the poll and argued that the three challengers were government stooges.
The publisher of the main opposition newspaper, Golos Respubliki, reported Monday that its publisher has surfaced in Belarus after disappearing three days before the election.
But Daniyar Moldashyov had refused to answer any questions when contacted by the paper’s editors and his brother. Belarus is a close ally of Kazakhstan.
"Of course this is a sensation for Western states," Nazarbayev told hundreds of flag-waving supporters after his victory was announced.