South Africans who engage in a war "under the flag of another country" that the government does not support, face losing their citizenship.

This, according to a new immigration law that was proposed in Parliament on Tuesday.

"There is currently no provision for the loss of citizenship by a naturalised citizen for engaging in a war that the republic does not support," Department of Home Affairs director-general Mkuseli Apleni told the portfolio committee on home affairs.

"The amendment of section 6 of the South African Citizenship Act of 1995 will provide that a naturalised citizen may not apply for retention of citizenship if he or she wishes to engage in a war that the government of the republic does not support, under the flag of another country.

It was estimated that around 1 100 South Africans were working as "security contractors" in Iraq after the US led invasion in 2003.

Government has since taken a tough stance on citizens fighting in foreign conflicts.

In 2006, the Prohibition of Mercenary Activities and Regulation of Certain Activities in Country of Armed Conflict Act was passed as a way of prohibiting "mercenary activity" and "to regulate the enlistment of South African citizens or permanent residents in other armed forces.

A separate amendment in the Bill proposes that a person have five years of ordinary residence in South Africa in order to qualify for a certificate of naturalisation as a way of reducing "interpretation" problems.

"Currently, the period required for cases of naturalisation is made up of one year of ordinary residence prior to making application, plus four years additional period of residence calculated by taking the number of actual days that a permanent resident resided in the republic in ever year," Apleni said.

"This provision of the Act poses serious interpretation problems, resulting in miscalculation of the period and ultimately granting naturalisation too early."

The Department also wants to amend aspects of The Births and Deaths Registration Act, including introducing a new law which to clamp down on corruption among funeral parlour owners.

"Currently, there is no provision authorising funeral undertakers to act as agents for deaths registration activities," Apleni said.

"In the amendment, funeral undertakers will be designated on compliance with prescribed requirements. This process is to ensure that persons handling death registration forms are authorised, in order to minimise corruption in the process."