The Communist Party chief of Xinjiang in China's far west is making a rare trip abroad, heading a delegation visiting neighbouring Kazakhstan on a trade mission.

In talks in Astana on Monday, Kazakh Prime Minister Alikhan Smailov told the group, led by Xinjiang Communist Party chief Ma Xingrui, that Kazakhstan would streamline cargo traffic into China by removing bottlenecks at border checkpoints.

"Given the task set by the two heads of state to increase trade turnover to US$35 billion by 2030, mutual trade between Kazakhstan and Xinjiang becomes even more important," Smailov said.

"We are ready to work together with our Chinese colleagues on this ambitious goal."

He said trade between China and Kazakhstan grew by 34 per cent to exceed US$24 billion last year, the highest in 30 years, and Kazakhstan would increase its goods exports to China by US$1 billion for 135 types of goods - items that were not specified in a statement from his office.

It is Ma's first trip outside of China since taking office in December 2021 during the Covid-19 pandemic.

His predecessor, Chen Quanguo, the focus of international criticism for reported human rights violations in the region, did not lead any foreign delegation as Xinjiang chief, while Chen's predecessor, Zhang Chunxian, headed a delegation to Kazakhstan in 2016 and another to Tajikistan in 2015.

Ma also held talks with Kazakh President Kassym-Jomart Tokayev, saying Xinjiang had become a conduit for cooperation between the two countries, which are seeking greater ties in areas including energy, agricultural products, industry and logistics.

"As a region of China, we are responsible for strengthening ties with countries in the west of our country," the Kazakh presidential office quoted Ma as saying.

"Kazakhstan is a priority area of mutual cooperation for us. In general, cooperation between China and Kazakhstan is implemented through Xinjiang."

China sees its ties with Central Asia - especially Kazakhstan, the region's richest state - as crucial to building the economy of its far west.

Beijing maintains that economic development goes in tandem with a strict security apparatus to crack down on what China says are separatist movements in Xinjiang.

A statement from China's embassy in Astana also described Kazakhstan as an important partner for Xinjiang's efforts to open up the region to foreign countries but did not give details about Ma's discussions with the Kazakh leaders.

Chinese President Xi Jinping visited Kazakhstan in September at the tail end of the pandemic, his first trip overseas in more than 2½ years.

Li Lifan, a specialist in Central Asia and Russia at the Shanghai Academy of Social Sciences, said Ma's trip was aimed at improving trade, especially by reopening cross-border motorways and railways that were closed during the pandemic.

But Elzbieta Pron, who researches China's ties with Central Asia at the University of Silesia in Katowice, Poland, said small, Kazakhstani-run companies were responsible for most cross-border trade in Xinjiang, and although China's borders had largely reopened since the pandemic, the disruptions and the perceived instability in Xinjiang had discouraged trade.

In addition to cultural exchange, Li said regional security continued to be a major area of cooperation, given Beijing's priority in thwarting separatist groups that seek to create an Islamic Xinjiang state independent of China.

Li said Xinjiang's party chief had assumed a new role of reaching out to Central Asian countries after the party's national congress in October.

China is increasingly concerned about the activities of extremist militant groups that could seep into its borders, especially as Afghanistan's Taliban struggle to keep militant groups at bay.

Soon after the United States withdrew its last troops from Afghanistan in 2021, Wang Yi, China's then foreign minister, told the Taliban that it had to cut ties with the East Turkestan Islamic Movement, a group Beijing blames for attacks in Xinjiang.

Raffaello Pantucci, a senior fellow at the S. Rajaratnam School of International Studies in Singapore, China had always had an interest in Central Asia but Chinese investment activities had remained constant.

"Everyone talks about it as the coming thing and the growing, the biggest potential opportunity for growth," he said.

"On the Chinese side, I see a mixed picture, frankly. I think on the one hand, you can see evidence of China trying to play off ... Central Asia against Russia in terms of hydrocarbons."

China has been importing cheap oil from Russia, which is under heavy sanctions from the West for invading Ukraine in February 2022.

In February this year, China hosted its first industry and investment forum with five Central Asian countries - Turkmenistan, Uzbekistan, Tajikistan, Kyrgyzstan and Kazakhstan - a grouping that did not include Russia.

Pantucci said its imports from Russia meant China had a stronger bargaining chip it could play against the Central Asian nations in negotiations over future projects and pipelines.

But Pron said the region was only a small source of energy for China.

"It's all about diversity and diversifying resources," she said. "I'm sure China will continue buying oil and gas from different countries."

She added that Central Asian nations had experienced power outages in major cities, and the Uzbek government announced in November it would halt natural gas exports to cope with the domestic electricity demand.

The power grids of Kazakhstan, Uzbekistan and Kyrgyzstan are connected, a legacy of their former status as Soviet republics.