Egyptians, blocked from the internet, are being offered a way by Google and Twitter to "tweet" by using a voice connection.

Engineers at Google, Twitter and SayNow, a company Google acquired last week, are making it possible for Egyptians to stay connected.

The service includes leaving a voicemail on international phone numbers listed on Google's official blog, which is instantly turned into a tweet.

"Like many people we've been glued to the news unfolding in Egypt and thinking of what we could do to help people on the ground," Ujjwal Singh, co-founder of SayNow, and AbdelKarim Mardini, Google product manager for the Middle East and North Africa, wrote on the blog.

"Over the weekend, we came up with the idea of a speak-to-tweet service."

The Google-Twitter service is just the latest option being made available to Egyptians to skirt the closure of the internet.

Web traffic volumes in Egypt slumped in a "co-ordinated fashion" shortly after midnight on Friday (local time) after demonstrators took to the streets demanding the ousting of President Hosni Mubarak, according to internet security firm Arbor Networks.

Opposition groups have urged Egyptians back on to the streets to demand the resignation of Mubarak, 82.

More than 90 per cent of Egypt's internet networks were down on Tuesday, the Geneva-based nonprofit internet Society said.

Old-fashioned dial-up connections to the internet are another option Egyptians have been offered.

At least 30 different dial-up services are being offered to circumvent the shutdown, said Paris-based French Data Network, a group founded in 1992 to make data accessible.

The group opened up one such "small window" on the internet network to help Egyptians access the web.

"This is definitely an open attack from a state against the internet," the group said on its website.

"FDN has decided to open a small window on the network."

FDN is giving them access on international lines through a dial-in number and entry codes.

"The infrastructure is already in place," said Benjamin Bayart, the head of the association, in an interview.

"As long as they have an international phone line, people can dial in."

Mobile phone voice services, run by local units of Vodafone and France Telecom, were restored on Saturday, after the Government ordered the companies to temporarily suspend operations.