Zimbabwe's ruling party says Robert Mugabe could lose his immunity and privileges as a former head of state and face expulsion from the party.

This comes after Mugabe last week told journalists that President Emmerson Mnangagwa had been imposed by the army and was in office illegally.

The party will meet

"Zanu-PF will have to meet to discuss these new developments… to review whether it is still necessary or not for him (Mugabe) to continue enjoying the status we had given him," the party's secretary for legal affairs, Paul Mangwana told the state-run Herald.

Apart from his comments to international journalists last Thursday, Mugabe has also been criticised for holding a meeting two weeks ago with a former cabinet minister, Ambrose Mutinhiri, who now leads an opposition party.

Mangwana said a former president had to be a "father figure" and "should not join active politics, particularly opposition politics".

Loss of privileges?

"If the party is satisfied that he has violated that principle, he will lose his Zanu-PF membership, he will also lose the privileges and immunities accorded to a (former) head of state and forfeit the respect he was enjoying," Mangwana added.

Mugabe resigned last November after the army took control of the country, and MPs from Zanu-PF and the opposition MDC began proceedings to impeach him. Mugabe kept his membership of the party though, and Mnangagwa has avoided criticising his former boss.

On Friday Mnangagwa's office said Mugabe was entitled to "express himself freely", but said "the nation has moved on".