The African National Congress (ANC) in KwaZulu-Natal on Tuesday reacted angrily to reports that President Kgalema Motlanthe was heckled during the Freedom Day celebration at Durban's Absa stadium.

Motlanthe's speech was disrupted when people sang loudly, forcing him to stop speaking while ANC provincial chairperson Zweli Mkhize persuaded the crowd to keep quiet.

The disruptions began when people sitting high up in the stadium complained about the sound quality.

ANC provincial chairperson Senzo Mchunu said media reports that the President was booed and heckled were not correct.

"This is far from the truth. There was a huge enthusiasm for the President.

"The crowd's displeasure was not a reflection of an attitude against the President. The crowds were merely expressing their dissatisfaction with the sound system which was of poor quality making them unable to hear the speeches of their leadership."

He said the crowd's dissatisfaction with the sound quality had started during the preceding addresses of Premier Sbu Ndebele and Arts and Culture Minister Pallo Jordan.

"The ANC chief whip Cyril Xaba was sent to the stands to test the sound quality and he himself expressed that those sitting at the upper level of the stands could not hear any sound," Mchunu said.

He said the media had failed to mention that the crowd was in a jovial and celebratory mood.

Earlier on Tuesday before the ANC statement was released, the Congress of the People (Cope) condemned in the "strongest terms" the "unruly behaviour" of the crowd.

"It is completely unacceptable that a sitting President of the country was subjected to such undignified behaviour," said Cope president Terror Lekota in a statement.

"This proves that the separation of powers between State and party are blurred. Events of this nature are held to celebrate national unity and cohesion.

"Cope condemns in the strongest terms the unruly behaviour...

"Cope calls on ANC president Jacob Zuma to distance himself from such behaviour and for the ANC to educate its members about the significance of national events," said Lekota.