MOSCOW (AP) _ Leaders of the republic of Kazakhstan promised today to solve social and economic problems fueling riots that have killed four people in an isolated city. New disturbances were reported.

The official Tass news agency said Kazakhstan's Council of Ministers set up a commission to outline improvements for Novy Uzen, a city of 56,000 people where arson and other attacks began last weekend.

Pravda reported that six people tried to seize a gas compressor station in the area on Thursday and that many workers in Novy Uzen, where the four people died, were staying away from work.

The Communist Party daily said only a quarter of the city's factory and office employees showed up for work Thursday. Only a bakery and food shops operated normally, Pravda said.

The rioters have demanded that all members of Caucasus ethnic groups be evicted from Novy Uzen. More than one-third of the population is from the Caucasus.

Native Kazakhs complain the Caucasus settlers dominate the oil industry jobs on which the city depends and receive preferential treatment in housing and other benefits.

The rioters also complain the settlers have set up private businesses that sell supplies in the desert city for exhorbitant prices.

Tass said cooperatives found guilty of abuses would be closed. It did not detail what other measures would be taken but quoted deputy Premier Oktyabr I. Zheltikov as saying that rapid development of the oil and gas industry had led to shortages of housing and food in Novy Uzen.

The social-economic package under consideration recalled similar pledges authorities made to quell rioting in another region of Central Asia, the Fergana Valley of Uzbekistan. An Uzbek government commission on Monday outlined plans to create 200,000 jobs, clean up polluting factories and grow more food in the valley, where rioting in late May and early June against minority Meskhi Turks killed 100 people.

Tass reported today that a legislative commission in Moscow would be set up to investigate the Meskhi Turks' problems.

The attack on the Novy Uzen compressor station was carried out at 3 a.m. Thursday by six people wielding metal rods and a rifle, Pravda reported. It said all six were detained.

Pravda said other attempts have been made to disrupt the town's water, electricity and a gas processing plant.

A curfew was imposed in the town after the rioting began, and foreign reporters have been barred from the region.

''A mass attack is being conducted now on autotransport enterprises, and calls for sabotage are ringing out,'' Pravda said.

At one transport business, a driver was quoted as saying his colleagues did not show up for work because they feared attacks.

Uzbekistan's Communist Party chief was replaced today, but there was no indication the move was related to the unrest.

Tass said Rafik N. Nishanov was relieved as Uzbek party first secretary because he had been appointed head of one of two chambers of the Supreme Soviet legislature in Moscow. Nishanov heads the Soviet of Nationalities, which reviews problems of the Soviet Union's more than 100 national groups.

The Uzbek party's Central Committee, meeting in the republic's capital, Tashkent, elected Islam A. Karimov, a regional party chief in the republic, to replace Nishanov, Tass reported.

It was the third change in a Soviet republic's leadership in two days.

Gennady Kolbin was let go Thursday as party chief in Kazakhstan so he could devote full time to his new job as chairman of the People's Control Committee, a watchdog operation over government ministries, Tass reported.

The new Kazakh party chief is 49-year-old Nursultan Nazarbayev, premier of Kazakhstan since 1984.

Also Thursday, the president of Azerbaijan, Suleiman Tatliyev, retired ''at his request'' and was replaced by Elmira Kafarova, Tass said.