South African foreign affairs spokesman Marco Boni said the matter was being explored at senior diplomatic levels and the intelligence service minister, Joe Nhlanhla, said he had ordered an investigation.
Police sources would not rule out a terrorist link to the surveillance while the German embassy said it could not comment on security issues
The camera was reportedly discovered on Wednesday after a security guard spotted a man changing video cassettes in a recorder hidden in a dustbin under the tree. The wiring linking the camera to the recorder was said to be very visible and crude. A spokesman for the police, to which the discovery was reported, refused to comment on the incident but said "terrorist or other motives" had not been excluded.
The most recent attack in South Africa which could be termed "terrorist" was the bombing last year of the Planet Hollywood restaurant in Cape Town by anti-American Muslim extremists. It followed the bombings of the US embassies in Dar es Salaam, Tanzania, and the Kenyan capital, Nairobi. But in South Africa or elsewhere on the continent, there have been no attacks on German-linked premises or individuals nor, it is believed, has Berlin's Pretoria embassy received any threats.
Separately, the South African opposition Democratic Party claimed its offices at parliament in Cape Town were under surveillance and that certain telephone lines had been bugged. The Democratic Party has labelled the bugging of the offices of Douglas Gibson, its chief whip, and other MPs, its parliamentary headquarters, as well as its national office and its Western Cape headquarters as South Africa's own Watergate scandal.
Among issues which the party wants explained is how some of the 24-hour surveillance equipment came to be mounted on certain buildings.
Ironically, disclosure of the electronic surveillance in Cape Town, which was discovered earlier this week, coincides with the final sitting of parliament for the year. This means that any questions to the government that are tabled by the Democratic Party will not be answered before Parliament resumes next year.