Dr Farooq Sattar said the decision was made by the Raabta Committee after meeting of ruling coalition in Karachi.
He said the security situation in the country particularly the Quetta bombings and the tension on the Line of Control are the reasons behind the decision.
Dr Farooq Sattar said there are intelligence reports that the terrorists could sabotage the long march.
He said the MQM decision has been communicated to Dr Tahirul Qadri.
Dr Farooq Sattar said his party will continue to provide moral support to Dr Tahir Qadri as there is convergence of views between the two on issues of the long march.
Lauding the MQM's decision‚ the Interior Minister Rehman Malik has said the Muttahida chief Altaf Hussain made the decision in the best interest of the country and democracy.
In a statement today‚ he said he is personally grateful to the MQM chief for this decision.
The Minister asked Dr Tahirul Qadri to withdraw his decision of the long march.
Rehman Malik said the lives of the Pakistani citizens are more precious than the long march. He hoped that the Tehrik-e-Minhajul Quran chief will positively respond to his appeal and announce to call off the long march.
PML-Q Chief Chaudhry Shujaat Hussain has termed the MQM decision of not participating in the long march a positive step.
He contacted MQM Chief Altaf Hussain by telephone and exchanged views about prevailing political situation in the country.
Hailing decision of MQM‚ renowned religious scholar Maulana Tahir Ashrafi said it will demoralize the extremists.