Trade union Solidarity's anti-crime campaign saw President Jacob Zuma receive a letter in his inbox every six seconds on Monday morning.

"At least 7 000 anti-crime letters have landed in President Zuma's email over the past 18 hours and thousands more are expected before tomorrow [Tuesday] at 10am," Solidarity deputy general secretary Dirk Hermann said in a statement issued at 10am on Monday.

Thousands of members of the public were signing in on the website www.dearpresident.co.za where an open letter to the President was published. It states: "Dear Mr. Zuma... we looked forward to your State of the Nation address with great anticipation. We were especially anxious to hear what you have to say about crime....

"Only 2% of your speech or 115 of your 4411 words were devoted to crime. In other words, in a speech that lasted almost an hour, one minute was spent on crime.

"You spent more time, or 132 words, welcoming guests of honour than talking about what you plan to do about crime."

The letter urges Zuma to use his address to Parliament on Tuesday, when he replies to the debate on his State of the Nation speech, to tell South Africa how his government planned to deal with high crime levels.

The letter is signed, "Concerned citizens of South Africa".

By 10:30am on Monday, the website posted a Twitter message saying: "The President is receiving one letter every six seconds!"

People who do not have access to email can SMS the word "crime" to 35960.

"Printouts of the letters will be delivered in mailbags at Parliament on Tuesday morning.

"This action comes after the Solidarity movement published a survey among its members, in which 73% said that crime is their single biggest concern.

"If crime is such a priority for Solidarity members, then it can be assumed that the broad Afrikaans and South African communities feel the same way about it," said Hermann.