Zimbabwe's President Robert Mugabe has been confined to his home, according to a statement by the office of his South African counterpart, Jacob Zuma.

South African officials said Zuma spoke to Mugabe by phone on Wednesday, amid a military takeover of government buildings in the Zimbabwean capital, Harare.

"President Zuma spoke to President Robert Mugabe earlier today who indicated that he was confined to his home but said that he was fine. South Africa is also in contact with the Zimbabwean Defence Force (ZDF)," the statement read.

"President Zuma has reiterated his call for calm and restraint and for the ZDF to ensure that peace and stability are not undermined in Zimbabwe," the statement continued.

A tweet sent separately on the South African government's official Twitter account said Zuma would be sending special envoys to the country in the aftermath of the crisis.

"President Jacob Zuma, in his capacity as Chair of SADC (Southern African Development Community), is sending Special Envoys to Zimbabwe and Angola in light of the unfolding situation in the Republic of Zimbabwe," it said.

In a televised broadcast earlier on Wednesday, a spokesperson for the Zimbabwean military said Mugabe and his family were "safe and sound", without providing further information about his whereabouts.

"We are only targeting criminals around him who are committing crimes that are causing social and economic suffering in the country, in order to bring them to justice," said Major General SB Moyo.

The Zimbabwean military made its move early Wednesday morning, quickly taking control of presidential and parliamentary buildings, state TV, and Harare's airport.

Tanks blocked off the entrances to government offices and troops patrolled streets in the capital, as many residents of the city decided to stay away from potential flare-ups of violence.

Mugabe, who is 93-years-old, is Africa's oldest leader, taking the helm of the country in 1980.