HARARE (Reuters) - Zimbabweans protesting against restrictions on imports of basic goods from South Africa forced the closure on Friday of the border post between the two countries and set fire to a warehouse, a police spokesperson said.

The Zimbabwean government said on June 17 it was suspending imports of products including bottled water, furniture, building materials, steel products, cereals, potato crisps and dairy products, most of which arrive via South Africa.

National police spokeswoman Charity Charamba said protesters in Beitbridge, a border town 600 kilometers south of the capital Harare, had barricaded a road with rocks and burning tires to prevent vehicles and people from crossing into South Africa.

She said a warehouse owned by tax agency ZIMRA and used to hold illicit goods seized from people crossing the border, had been set alight by the protesters, and that the border post was still closed as at 9 p.m. local time.

More than 85 percent of working age Zimbabweans have no formal job and most people make a living by buying goods in South Africa to sell in Zimbabwe.

"The extent of the damage is not known. If you have such demonstrations, other criminal elements also join in and it becomes (a) free-for-all," Charamba told Reuters.

Residents and shop owners in Musina, a town on the South African side of the border, had earlier blocked vehicles and people crossing from Zimbabwe, saying Harare should lift the suspension on imports, said Loud Ramakgapola, a senior official with Beitbridge Town Council.

Beitbridge is the busiest road border post in southern Africa and the place where goods flow between South Africa and countries such as Democratic Republic of Congo, Zambia and Malawi as well as Zimbabwe.

ZIMRA said in a statement that Zimbabweans should comply with the import ban and that the police were working to restore order after Friday's "minor" incident.

(Reporting by MacDonald Dzirutwe; Editing by Catherine Evans)