A unit of Chinese soldiers arrived in Mali on Thursday to strengthen the United Nations peacekeeping force in the troubled west African nation's rebel-infested north, sources told AFP.

A foreign diplomatic source in the capital Bamako said 245 Chinese troops would join a 150-strong contingent which has been stationed since December in Gao, the largest city in Mali's northern desert and the target of sporadic Islamist violence.

A source from the UN's MINUSMA force confirmed the deployment but said he wasn't immediately able to provide details.

UN peacekeepers took over security in July last year from the pan-African AFISMA military mission, which had been supporting French troops who entered Mali to push back an Islamist incursion which was advancing on the capital.

France is winding down its deployment from a peak of around 5,000 soldiers but is to keep 1,000 troops in Mali beyond the Spring.

MINUSMA is made up largely of Africans but China offered in May last year to supply more than 500 troops in what was to be its biggest contribution to UN peacekeeping.

The mission played a key security role in presidential polls last year which saw former premier Ibrahim Boubacar Keita become the country's first democratically elected leader since a March 2012 military coup.

UN officials have acknowledged that peacekeepers face the threat of guerrilla attacks and will encounter a number of logistical difficulties in northern Mali's harsh environment, where water is scarce and temperatures sore above 40 degrees Celsius.

Under-Secretary-General for Field Support Ameerah Haq last year called MINUSMA "one of the most logistically challenging missions the United Nations has ever launched".

Jihadists in northern Mali were weakened by the French-led military campaign but remain active, hiding out in the vast desert and committing sporadic attacks against foreign and Malian troops.

UN Secretary General Ban Ki-moon said in a report released in early January that MINUSMA had grown to 5,539 soldiers by December 16, around half of its planned eventual strength of 11,200.