Samsung Electronics (KRX:005930) and SK Hynix (KRX:000660) could face delays to their chip expansion projects after the National Ready-Mixed Concrete Transport Workers' Union suspended concrete deliveries across the Seoul metropolitan area, Reuters reported Friday.

The union, representing around 8,000 members, began the strike on Monday in its demand for higher transport rates, among other claims, the report said.

Blocked deliveries from two ​concrete plants in Pyeongtaek on Thursday halted concrete pouring at Samsung Electronics' chip plant construction site, while cancelled deliveries stopped construction work at SK Hynix's Yongin ​chip plant, it said.

SK Hynix said the immediate impact is expected to be contained after adjusting construction schedules. Samsung Electronics declined to comment, while the union did not respond to media inquiries at the time of reporting, Reuters said.

Shares of Samsung Electronics jumped nearly 8% at market close, while those of SK Hynix added over 2%.

(Market Chatter news is derived from conversations with market professionals globally. This information is believed to be from reliable sources but may include rumor and speculation. Accuracy is not guaranteed.)