Unionized Seoul subway workers have called off plans to go on strike Wednesday after reaching a last-minute agreement with a Seoul subway operator on retirement age and severance pay, both sides said.

Union members of Seoul Metro, a public corporation that runs Seoul subway lines No. 1 through 4, were scheduled to walk off the job from 9 a.m. Wednesday after repeatedly failing to find middle ground on various outstanding issues with the management.

However, the two sides reached a final agreement late Tuesday night, averting a massive walkout that could have largely disrupted mass transportation in Seoul and the surrounding areas in Gyeonggi Province, which are already partially affected by an ongoing strike by unionized workers of the state-run rail operator.

Under the agreement, the current practice of progressively increasing severance pay will be scrapped starting next year and the retirement age of workers will also be moved up in phases.

Commuters in the capital city experienced minor disruptions Wednesday as the number of trains on subway line No. 3, jointly operated by state-run Korea Railroad Corp. (KORAIL), were brought down by an average of around 20 percent, KORAIL said.

More than 6,500 unionized KORAIL workers continued their strike for the 10th day in protest against a government decision to set up a new rail operator that they claim is the first step toward privatization of the rail operator.

Daily bullet-train KTX services were reduced by 12 percent, and the operation of the normal-speed Mugunghwa trains were also somewhat affected, it added.

Amid the prolonged strike, prosecutors said they will additionally seek arrest warrants for 18 striking KORAIL workers for refusing to respond to summonses by prosecutors as part of an investigation.

The move comes after the KORAIL management filed a charge against a total of 190 union members for instigating the "illegal walkout," saying that their action caused huge financial losses.

"Unlike previous arrest warrants issued against union leaders, the second round of warrants target union members leading the walkout on site," said a prosecutor of the Supreme Prosecutors' Office.

On Monday, local courts already approved the prosecution's request to arrest 10 leading members of the KORAIL union.

With court-issued warrants, both police and prosecutors are pursuing 10 unionized workers, including Kim Myung-hwan, the leader of the KORAIL union, to bring in for questioning, prosecutors said.

KORAIL workers have criticized the planned establishment of the affiliate, claiming that it is the first step toward privatizing the state-run company, which they say could result in massive layoffs and fare hikes.

The company has denied the claim, saying the new unit will be 41 percent and 59 percent owned by KORAIL and state-run investors, respectively, and that private firms will never be allowed to buy stakes in it.

The new service will run from Suseo-dong in southern Seoul to the southern port city of Busan. After several delays, it is expected to begin operations in 2016. (Yonhap News)