The Human Rights Watch group has condemned the Kazakhstan's presidential election process as grossly unfair.

With just four days to go before the ballot, the group issued a statement saying coercion, threats and repression of opposition activists have characterised the presidential campaign.

In a letter to the Organisation for Security and Cooperation in Europe, the OSCE, the group said the OSCE should protest by postponing the establishment of its field office in Kazakhstan.

The OSCE has already criticised the election process and warned that it would not recognise the results if voting goes ahead.

The President, Nursultan Nazarbayev, is widely expected to win Sunday's vote.