Snow flurries blew through South Africa on Tuesday, closing several border crossings with Lesotho and dusting parts of the country in white as residents poured into the streets to watch the snowflakes fall.

"It's amazing, Merry Christmas!" said Roger Gibbs, driving through a leafy suburb in commercial hub Johannesburg where the trees were frosted in white -- the first time in five years.

Snow falls annually in the mountains of South Africa and Lesotho, which even hosts a ski resort. But some high-altitude border posts between the countries received so much snow Tuesday that they were forced to close.

Heavier snowfall in the Western mountains closed the main highway linking Johannesburg to Durban, Africa's busiest port, for several hours.

The snowfall swept north across Johannesburg, coating southern neighbourhoods in the early morning and then moving toward the Sandton financial district.

"Amazing! Never happened in my life," said Mizundile Eseu, 23, a security guard.

The South African Weather Service said six of the country's nine provinces had snowflakes on Tuesday, with snow expected through the night in Johannesburg.

Authorities urged motorists to take care on the roads, with few drivers used to travelling on snowy streets, but no accidents had been blamed on the snow, according to police.