A grenade was thrown at the residence of J C Weliamuna, who heads the Sri Lanka chapter of Transparency International and has also appeared in several cases of human rights abuses and police brutality.
On Monday senior lawyer R K W Goonesekera handed over a motion signed by 326 lawyers to the executive committee of the Bar Association of Sri Lanka (BASL), the island's top lawyers' body saying the country was heading towards anarchy.
The motion said most of Weliamuna's work involved "actions against the State and that in the immediate past leading up to this attack, he had appeared in several matters against the Police and the National Defence Establishment."
"We are all of unanimous and resolute consensus that with this attack on our colleague 'summons have been served on the doorstep of the BASL', that as the Association representing Attorneys at Law of the Supreme Court of this Republic who have proclaimed a public oath to uphold and protect its Constitution, we have been charged with a bounden duty; to ensure that the governance of its peoples are subject to the Rule of Law and that liberties of its citizenry are protected at any cost," the motion said.
"We are compelled to admit that we as the BASL have not been discharging this duty to the level expected, thus inviting the status quo to deteriorate gradually to this level which we witnessed last night at the residence of our own colleague.
"We fear that we cannot ignore this situation any further and allow it to escalate to the only possible next level; which we seriously apprehend as absolute anarchy."
The motion called upon the association to set up a method where lawyers were made available for victims of human rights or actions seeking good governance and accountability were given legal assistance.
The attack on Weliamuna drew condemnation from rights bodies and the international community.
The European Union said the attack was just the latest in a series that have been directed against ordinary citizens of the country.
"The EU notes with concern the trend in attacks and threats on journalists, civil society organizations and now a lawyer," it said in a statement.
"Although there is no indication on the reasons or on the perpetrators of this attack, it is assumed that the attack may have been against the important human rights and anti corruption work Mr.Weliamuna was involved in."
The United States also called for an immediate investigation on the attack.