Almaty - Kazakhstan detained several vocal opponents of land reform who planned to take part in Saturday protests, activists said on Wednesday, in an apparent attempt to preemptively derail the rallies.

Challenging the authority of President Nursultan Nazarbayev, who has run the Central Asian nation since 1989, hundreds of people have protested in several cities over the last four weeks against plans to privatise large swathes of farmland or lease them out to foreigners.

Yielding to the protests, a rare public display of discontent in the oil-rich former Soviet republic, Nazarbayev this month put on hold the reform, but warned that further rallies would not be tolerated.

His government established a commission to review the reform and invited some of its opponents to join it. But shortly after the first meeting last Saturday some activists quit the body and called for nationwide protests on May 21, 2016.

Late on Tuesday, police detained and put in front of court several activists in the capital Astana, biggest city Almaty and oil hub Atyrau, their relatives and supporters said.

In Astana, a court then detained activists Makhambet Abzhan and Maksat Nurypbayev for 10 days each, Abzhan's wife told Reuters by telephone, adding that her husband had been charged with hooliganism.

In Almaty, activists Bakhytzhan Toregozhina and Suyundyk Aldabergenov were put into custody for 15 days each for planning an illegal public rally, fellow activist Amirzhan Kosanov said.

In Atyrau, the city where the first protest took place, activists Max Bokayev and Talgat Ayanov were each sentanced to 15 days custody on the same charges in the early hours of Wednesday, activist Asel Nurgaziyeva wrote on her Facebook page.

Local governments in all three cities this week refused to allow the protests, making them illegal under Kazakh law.

“The establishment of the land (reform) commission implied that the government has limited all negotiations to that body and everything happening outside of that platform has been ruled illegal,” said political analyst Dosym Satpayev.

Even small-scale protests have long been very rare in Kazakhstan, partly because of its restrictive legal and political environment but also thanks to its status as the richest nation in the ex-Soviet Central Asian region.

But the plunge in the price of oil, Kazakhstan's main export, has put its economy on the brink of recession and forced the authorities last year to allow the national tenge currency lose nearly half of its value against the dollar.