The labor union of ING Life Insurance announced on Wednesday it will go on a strike later this month as the company refused to guarantee its members’ job security.

The labor union will start the strike between July 25 and 31, to last for an indefinite period.

“We are going on a strike because the company lacked sincerity when negotiating about employment security and the issue of irregular workers. The company deliberately delayed discussions so there was no progress,” said Lee Gi-cheol, the union head.

The labor union is also fighting by pushing to start and finish the working day at the exact promised time. All union members are encouraged to get off work at 6 p.m., participate in the meeting and leave work.

The announcement of the strike draws attention as ING Life Insurance recently emerged in the market for mergers and acquisitions. KB Financial Group and AIA Group took part in the bid on Monday to acquire the local unit of the global insurance group. Insiders expect that the strike may hold back the announcement of the preferred bidder.

ING Life Korea is the fourth-largest in the country by market share, and is known to be worth around 3.5 trillion won ($3.04 billion).

Analysts said if KB Financial takes over the life insurer, the lender will be able to use its 1,160 local branches to handle ING Life’s non-banking businesses such as bancassurance, according to Yonhap News.

For AIA, it will lift its ranking in Korea to fourth from its current 10th, a significant expansion in Asia’s fast-growing insurance market, they said.

Meanwhile, Yonhap News also reported that Korea Life Insurance, the country’s second-largest life insurer, submitted a bid to buy the southeastern operations of ING Group, which include operations in Malaysia and Thailand, according to industry sources.

By Park Min-young  (claire@heraldcorp.com)