Zambians wary of electoral fraud flocked to the Internet and social media on Tuesday to expose any irregularities in a closely contested presidential and parliamentary poll.

Using text messages, Twitter, Facebook and email, Zambians reported scores of perceived voting glitches and irregular poll practices by early Tuesday afternoon -- the first such use of mobile technology in the southern African nation.

The election, pitching President Rupiah Banda against long-time rival and opposition leader Michael Sata, saw long queues of voters initially as some polling stations opened late.

Wow! There are still areas where polling is yet to start. Anyone encountered this issue? one Zambian said on micro-blogging site Twitter.

The Electoral Commission of Zambia said it would extend voting by up to three hours at affected polling stations to accommodate voters who had been unable to cast their votes.

Frustrations boiled over at one station and the crowd went on the rampage, burning voting materials and damaging five vehicles. Police said four people were arrested.

The monitoring campaign under the banner Bantu Watch ( is based on crowdsourcing -- using data from online users -- and is based on technology developed by the Kenya-based Ushahidi website.

The Ushahidi technology was first used to map outbreaks of post-election violence in Kenya in early 2008, and has since been used to monitor elections in Nigeria and in the rescue effort after the 2010 earthquake in Haiti.

Most of the reports of irregularities on came from the capital, Lusaka, including reports of vans carrying ballot papers being burned and allegations that candidates were buying votes by distributing drinks to voters.

At one point, many Zambians said in mobile posts on Twitter that the monitoring site had been blocked and they could not access it through the Internet. The website later became available again.

Thank goodness #bantuwatch is back online. Going forward this site should become a media mainstay for all important national matters, one Twitter user said.

Some reports were confusing.

Ladies with nail paint on their right thumb are being advised to remove the paint before they can be allowed to vote, tweeted Mutheliso Phiri from Kitwe in Zambia's Copperbelt province.

Observers from the European Union and the regional SADC group have also been keeping an eye on events on the ground, although one Bantu Watch report questioned the dedication of monitors spotted in a fast-food restaurant in a Lusaka mall.

It's like they came for a holiday, the comment said.

(Editing by Giles Elgood)