African National Congress Youth League (ANCYL) leader Julius Malema seems to be on thin ice, if statements made by Deputy President Kgalema Motlanthe on Tuesday are anything to go by.

Malema probably received his sternest warning yet from the ruling party, with Motlanthe saying there was "no doubt" that he would face disciplinary steps relating to an ugly public spat with the South African Communist Party (SACP).

"The ANC always believes the first step is to correct [a person]... that is why we would always call people to order with the aim of correcting them," said Motlanthe.

"But, of course, if that does not produce any progress, no doubt the leadership of the ANC will take appropriate decisions about that.

"Nobody defies the ANC and gets away with it," Motlanthe told reporters in Johannesburg.

The African National Congress, after its national executive committee meeting (NEC) on Monday which was attended by Malema, "called on all members to refrain from fuelling tensions and to allow for the NEC to raise its displeasure with the SACP".

But on Tuesday morning, Malema told reporters in Pretoria that "the yellow communists are driven by greed", called on the youth to "go to the streets, let's fight," and repeated that SACP deputy general secretary Jeremy Cronin would be taught a "lesson".

The tension between the ANCYL and the SACP started when Cronin criticised Malema's call for the nationalisation of mines.

"Comrade Malema hasn't always helped his case with off-the-wall sound-bites.

"The impression of a policy being made on the hoof, individualistically, is reinforced by the fact that we are yet to see any serious attempt at a collective policy document on this matter from the ANCYL."

Malema responded to this by describing the piece penned by Cronin as "openly reactionary".

He said he did "not need the permission of white political messiahs to think".

While the two parties seemed to kiss and make up in a statement on November 25, the sparks flew again last week, when SACP delegates booed Malema at their conference in Polokwane.

After this, Malema sent Cronin threatening SMSs and the ANCYL issued a statement on Monday insulting several leaders, and linked the divisions to the 2012 succession debate in the ruling party - a big no-no within the ANC.

Motlanthe also made that clear on Tuesday.

"The NEC will issue a statement for that process [the succession debate] to start. Anything outside this, nothing will be taken seriously. In fact, whoever says what, is out of order."

The ANC NEC - which condemned the booing incident - requested a report on it from the SACP delegation.

The NEC will consider the report early next year.

"It will no doubt set disciplinary procedures in motion," said Motlanthe.

He added that a similar spat on provincial level within the ANC in the Western Cape between Ebrahim Rasool and Max Ozinsky, ended with both being suspended.

But Malema and Cronin were both NEC members, which made their public disagreement even more serious, said Motlanthe.

"Therefore this would be regarded as more grave," he said.

"That is why I make mention of the fact [the Western Cape suspensions]. I have no doubt this [the report] will set in motion disciplinary procedures," repeated Motlanthe.