Chinese Premier Wen Jiabao has said that land seizures by local authorities are a key threat to rural stability.
Farmers who lose land often have no legal recourse
He said land grabs and a lack of proper compensation for those affected was sparking "mass incidents".
His comments were published a day after the government said public disturbances in 2005 had risen more than 6% on 2004.
The latest mass protest took place in the southern city of Shenzhen on Thursday, after police shut down night spots as part of an anti-vice campaign.
"We absolutely can't commit an historic error over land problems," Mr Wen said, in a speech made on 29 December but only published in China's state-run press on Friday.
RECENT LAND DISPUTES
6 Nov 2004: Paramilitary troops put down an uprising of 100,000 farmers in Sichuan province
10 April 2005: 20,000 peasants drive off more than 1,000 riot police in Huaxi, Zhejiang province
11 June 2005: Six farmers die in a fight with armed men in Shengyou, Hebei province
29 July 2005: Villagers in Taishi, Guangdong try to oust mayor
6 Dec 2005: Police shoot dead protesters in Dongzhou, Guangdong
14 Jan 2006: Police break up protest in Sanjiao, Guangdong, over land grabs
"Some places are unlawfully occupying farmers' land and not offering reasonable economic compensation and arrangements for livelihoods, and this is sparking mass incidents in the countryside," he said.
He said farmers were paying the price for China's rapid urbanisation.
Correspondents say the comments show how worried Beijing is becoming about instability in the countryside, where the majority of China's population still lives, while corrupt local authorities often ignore orders from the central government.
In one recent incident, villagers in southern China's Guangdong province said a teenage girl was killed last week when police broke up a protest over land taken over for development, a charge the local authorities denied.
There was also a large protest about job losses on Thursday, in the city of Shenzhen.
Hong Kong newspapers said there were scuffles between police and workers from the closed businesses, which included discos, karaoke bars, and massage parlours, outside the city government's offices.
One report said some protesters were rounded up and taken away on buses.
Correspondents say the Shenzhen authorities are trying to clean up the city, which has a reputation for crime and a thriving sex industry.
They say prostitution, virtually eradicated in the early decades of Communist rule in China, is again rife, and that massage parlours and karaoke bars are often fronts for brothels.