The local government of a tourist town in Yunnan province had to make an emergency appeal to police after more than 100 shop tenants stormed its office seeking help in a lease dispute with the head contractor of a market.

Three police officers and three protesters were taken to hospital with injuries, but none were considered life-threatening, officials said. The incident occurred in Lijiang Old Town, a Unesco World Heritage site in the province's northwest known for its orderly system of waterways, bridges and traditional buildings, built by the Nakhi ethnic minority.

On Friday morning, tenants arrived at the Huahui Industrial Products Market to find the contractor had blocked the main entrance after the rental agreement had expired, according to a statement about the incident the local government posted online.

Angry tenants broke the gate and the market management office called police, leading to a stand-off, the statement said.

Later, the tenants rallied at the old town's government office building to file a petition. The situation spiralled out of control and protesters went on a rampage inside the offices. There were physical altercations with staff working in the petition office, the statement said.

Additional police were deployed after the public security department declared an "emergency event". The situation was brought under control about an hour later, at 11.10am.

The tenants and their contractor had not reached an agreement on a new lease, the publicity office said.

Small-business owners in the old town have grown increasingly discontented with the local government in the past year. In July, the town's publicity office said two vendors were severely beaten up by at least seven urban management officers, known as chengguan in Putonghua.