BEIJING, Aug 2 (Reuters) - China has jailed another 31 people, including four government officials, for their roles in a massive brick kiln slave labour scandal that sparked nationwide outrage, state media said on Thursday.

Hundreds of farmers, teenagers and children were forced to work in scorching kilns in the northern province of Shanxi, enduring prison-like confinement and brutal beatings and kept at bay by dogs.

The workers, some of whom were mentally disturbed, were forced to work before the kilns had cooled down as owners tried to maximise production and meet demand from a booming construction industry.

TV pictures showed many of the emaciated workers suffering festering burns to the feet and body.

Five local courts in Shanxi sentenced a second batch of 31 defendants to prison terms between 18 months and five years on Tuesday, the People's Daily and Xinhua news agency said.

Two "industrial and commercial department" officials and a police officer in a township in Hongtong county, at the centre of the scandal, were jailed for dereliction of duty that allowed the kilns to exist for years, the People's Daily said.

Zhao Yanbing, who guarded a kiln in the township, was sentenced to death last month for inflicting a beating that led to the death of a worker who laboured 14-16 hours a day for little or no pay with some 30 workmates.

Twenty-eight others -- owners, managers and enforcers of the brickworks -- were imprisoned for up to life on charges of forced labour, illegal detention and mayhem in a massive sentencing on July 17.

Among those jailed on Tuesday was Shang Guangze, an official with the labour and social security bureau in Yongji city, who received two years for abuse of power, the People's Daily said.

Shang was ordered to send a 17-year-old worker just freed from a kiln home in May, but he took him to another brickworks run by his relatives instead and demanded 300 yuan ($40) from the boy, the newspaper said.

Shanxi has also announced penalties against 95 officials, but their ranks are conspicuously low. Authorities said there was no evidence of official corruption or collusion.

More than 570 workers, including 41 children, have been rescued in Shanxi and neighbouring Henan and nearly 160 people have been arrested, Xinhua said.

The scandal only came into light after more than 400 Chinese parents posted an online petition and turned to reporters for help to find their missing children, many of whom were kidnapped or cheated to be sold to the Shanxi kilns.