Oil giant Shell's plans to prospect for shale gas in the Karoo could affect South Africa's bid to build the world's biggest radio telescope, MPs heard on Wednesday.

Science and technology deputy director-general Val Munsami said Shell's plans were starting to raise questions among international partners.

They were asking how such exploration might impact on the Square Kilometre Array (SKA), he told Parliament's science and technology portfolio committee.

South Africa and Australia were shortlisted in 2006 as locations for the SKA project.

The SKA will cost about €2-billion to build, and require between €150-million and €200-million a year, for 50 years, to maintain and operate.

The radio telescope – brainchild of a consortium of major international science funding agencies in 16 countries – comprises 3 000 giant antenna dishes, each the height of a three-storey building.

Astronomers plan to use the SKA to peer back through time, across vast distances, to investigate the history of the universe and when the first stars were formed.

The SKA core site in South Africa is near Carnarvon in the Northern Cape, where many of the dishes would be erected.

The plan also includes locating receiving stations, each comprising about 30 antenna dishes, in eight other African countries, some as far away as Ghana and Madagascar.

An announcement on who has won the bid will be made early next year.

Munsami said on Wednesday questions about Shell's plans were starting to "creep in" to South Africa's international lobbying strategy.

"Obviously, from a SKA perspective, we are concerned about it... In terms of the international lobbying strategy, it's starting to creep in as well; the international partners are starting to ask where this is going and how it will impact the SKA."

The department was looking at the implications of the oil company going ahead with its exploration for shale gas.

"One key piece of legislation we have in place is the Astronomy Geographic Advantage Act, which regulates the area in terms of radio interference," Munsami told the committee.

"Obviously we will be looking at whether, in terms of exploration, there is any radio interference. If there is, we will have to have that discussion in terms of the regulatory framework."

A management authority was being put in place within the department to deal with the matter, and "to ensure regulations are fulfilled in terms of protecting the SKA".

There was also "ongoing" discussion between his department and the department of energy on the matter, Munsami said.

Committee chairman Nqaba Ngcobo noted the Astronomy Geographic Advantage Act gave the sole right to regulate the zone in which the SKA would operate to the Minister of Science and Technology.

"So I think that's not a problem... There is no way Shell can go ahead with that; the Act does not allow it. It can't," he assured members.

Anita Loots, associate director of South Africa's SKA team, said a key issue was that nothing untoward happened while radio frequency interference (RFI) tests were being conducted in the Karoo.

A team from the international SKA technical committee is currently in the country to carry out such RFI tests. Similar tests are being conducted in Australia.

The team's report will contribute towards determining which of the two countries win the bid.

"The key issue for us is that while the RFI measuring campaign is going on in South Africa and Australia, that there is nothing happening in the Karoo that requires people to carry a cellphone, or some sort or radio transmitting equipment, or whatever can actually impact on that measurement," Loots said.

"Because... although the fracking may happen quite a bit later, the immediate effect of it is if there are very strong radio signals in that area because of the exploration."

The "fracking" referred to is hydraulic fracturing, a technique for extracting shale gas from deep underground by pumping a pressurised mixture of water, sand and chemicals down drill holes.