Mozambique is clamping down on human trafficking amid reports the southern African nation has become a key route for adults and children sold into forced labour and prostitution, a government spokesman said.

The country's parliament is expected to approve a bill next month that will raise prison sentences for smugglers and others engaging in the practice, cabinet spokesman Luis Covane said on Wednesday. Those caught trafficking humans currently face jail terms ranging from two to eight years.

"We are seriously concerned over the continued reports of trafficking in Mozambique, which is now regarded as a corridor and a safe heaven for these wrongdoers," Covane said.

"We will adopt legislation that will discourage this practice, which is very common in Mozambique and the entire southern African region," he added. Covane declined to say what sentences traffickers would face if the bill became law.

Mozambique has not prosecuted anyone for human trafficking. Efforts to do so have been handicapped by the former Portuguese colony's general tolerance of child labour, which is common in its rural areas, as well as its weak border controls.

Smugglers have seized on the country's complacent attitude, arranging for young men and boys to be sent to work on farms and mines, and young girls to be sold into domestic servitude and to brothels in neighbouring southern African nations.

Authorities said the smuggling networks were usually small operations run by Mozambicans and South Africans. South Africa is one of the major destinations for those who fall prey to the human traffickers.

An estimated 1,000 Mozambican women and children are trafficked to South Africa each year, according to a recent study by the International Organisation on Migration (IOM).