The bereaved families of the victims of April's deadly ferry sinking voted late Wednesday to reject a bipartisan deal that allows the ruling party to have a say in the choice of a special counsel to be tasked with uncovering the truth behind one of the country's deadliest maritime accidents.

It is the second time the families have rejected a bipartisan deal on a special bill aimed at determining the truth behind the tragedy, dealing a blow to both the ruling and opposition parties.

The 6,825-ton ferry Sewol capsized off South Korea's southwest coast on April 16, leaving more than 300 people dead or missing.

The tragedy has become a political football in South Korea as critics argue that the government's initial failure to properly respond to the disaster contributed to the high death toll.

After weeks of wrangling, the ruling Saenuri Party and the No.1 opposition party, the New Politics Alliance for Democracy (NPAD), reached a deal Tuesday under which the ruling party would appoint its share of a seven-member panel to be tasked with choosing the special counsel only after seeking the approval of the opposition party and family members of the victims.

The deal was met with immediate objections from the families as well as some members of the opposition party, who argued that it fails to reflect their demands for an ad hoc investigative committee with the right to investigate and indict. They also argued that the ruling party should not be allowed to select any of the panel members.

By law, the ruling and main opposition parties each select two members for the panel, which then recommends two special counsel candidates to the president. The president appoints one of the two.

In Wednesday's vote, 132 of the 176 families who gathered in Ansan, just south of Seoul, voted in favor of a bill that would give the ad hoc investigative committee the right to investigate and indict, according to a committee of the victims' families.

The investigative committee is to be set up under the bill.

"The ruling and opposition parties didn't discuss the issue of the right to investigate and indict, and are asking us to accept a bill they haven't explained to us," Yoo Kyung-geun, a committee spokesman, said.

The opposition party has ruled out another renegotiation of the bill, apparently mindful of the criticism it would face if it breaks another bipartisan deal.

NPAD earlier broke a deal with the ruling party to follow the law in choosing members for the special counsel. (Yonhap)