Deputy President Kgalema Motlanthe on Wednesday took African National Congress Youth League (ANCYL) leader Julius Malema to task for referring to Democratic Alliance (DA) leader Helen Zille as a cockroach.

"We must put our points across without trying to demean each other," he told the National Assembly during question time.

Motlanthe was responding to Lance Greyling of the Independent Democrats (ID), who said that he had been shocked to hear Malema at the weekend refer to Zille as "a cockroach that needs to be driven from her office".

"Surely you would know, honourable Deputy President, that this term was a weapon in the Rwandan genocide and has absolutely no place in our political discourse," Greyling said.

Given that, he wanted to know from Motlanthe, as the country entered the municipal election period, what measures would be put in place to ensure that such words and actions were not used to divide the population even further.

"I do agree with you," Motlanthe responded.

He said that he really did not like the fact, that even though human beings were part of the animal kingdom, "we tend to use other animals to insult each other".

"Nobody takes offence when it is said you are a lion, or a blue bull," he said. So... when we go campaigning, we must not be disrespectful, we must not use inciteful language.

"We must put our points across without trying to demean each other. And I think the fact that the gentleman you alluded to referred to a good lady, like she's a cockroach, I think it's a bad thing myself. I think it's downright simple bad manners," Motlanthe said.

During an ANCYL rally in Stellenbosch on Saturday - attended by President Jacob Zuma - Malema told supporters that Zille was a cockroach and must be voted out of power.

"You have put a cockroach in Cabinet and we need to remove that cockroach by voting the ANC into power," he said.

Responding to another question on whether South Africa remained on course to create a non-racial society premised on the principle that South Africa belonged to all who lived in it, Motlanthe said this remained a collective responsibility.

"We must continuously reiterate that South Africa comprises people who originate from many parts of the world who have brought with them values and cultures that over the intervening years have been blended into a rich tapestry of diversity," he said.

Perhaps the greatest challenge was not merely striving to be tolerant of this diversity, but to actively explore it, engage with it and ultimately to understand and harness it.

In this way a central vision that defined the parameters of progressive and critical discourse was one that said South Africans were one people with one destiny.

"And it is this galvanising vision that will sustain our spirit in the course of fighting against poverty and inequality, and that will keep us as a people focused on building a non-racial future for all.

"It, therefore, remains our collective responsibility to keep championing the vision of building a united, non-racial, non-sexist, democratic and prosperous South Africa," Motlanthe said.