Safety hazard: A pickup truck plunged into a sinkhole after a section of Rama II Road’s inbound lane collapsed near KM 29+300 in Samut Sakhon yesterday morning. The sinkhole — about 1 metre deep — also ruptured a water pipe, sending tap water gushing out and flooding the surrounding area.

The government is poised to halt state-owned construction projects or cancel contracts with contractors that fail to protect public safety, after another accident on Rama II Road on Saturday added to a string of recent construction fatalities.

Speaking after another road collapse was reported on the inbound lanes of Rama II Road in Muang district of Samut Sakhon province, Prime Minister Anutin Charnvirakul said repeated accidents had left the government with no choice but to rely on administrative orders, rather than civil contract mechanisms, to protect the public.

"When accidents happen repeatedly, pursuing civil remedies under contracts is simply ineffective," he said. "This is a legal matter. The government must use administrative power to order construction suspensions or contract terminations when public safety cannot be guaranteed."

The accident on Saturday was the third in a week.

A launching gantry crane collapsed on Thursday at an elevated expressway project on Rama II Road in Samut Sakhon, killing two people and injuring five others. It followed a separate accident in Sikhiu district of Nakhon Ratchasima on Wednesday, when a crane fell onto a passenger train, killing 30 people and injuring 69.

On Thursday, Mr Anutin ordered the Ministry of Transport to terminate two contracts with Italian-Thai Development Plc (ITD), the main contractor involved in the two projects.

He also instructed the ministry to initiate legal proceedings, blacklist the contractor and hold an emergency meeting to review safety measures across all transport-related construction projects.

The decisions were made following consultations with the Council of State and the Attorney General.

Mr Anutin said the accidents had severely shaken public confidence and posed serious threats to lives and property, particularly on Rama II Road, a key artery linking Bangkok to southern provinces.

Addressing public concerns about another incident on Rama II Road on Saturday, he said the road subsidence yesterday morning was caused by a burst water pipe and human negligence, not by flaws in structural design or construction methods.

The collapse occurred at 6.30am near kilometre marker 29+350 on the inbound parallel lane in Muang district, Samut Sakhon, causing a pickup truck to fall into a sinkhole. No injuries or fatalities were reported.

The Department of Highways said the damage was caused by the rupture of a 1,000mm water pipe operated by the Samut Sakhon municipality during excavation and pipe-connection work, which led to soil erosion beneath the road surface.

Emergency crews were deployed to manage traffic and secure the area while repairs were carried out.

Mr Anutin acknowledged the concerns, adding the most serious risk lies in structural failures related to lifting operations and construction practices, which are preventable if proper procedures are followed.

"If administrative orders are issued and officials fail to act, civil servants could face legal consequences under Section 157," he warned, referring to dereliction of duty under the Criminal Code.

Structural engineering experts have also weighed in on the problem.

Prof Amorn Pimanmas, president of the Structural Engineers Association of Thailand, said the road subsidence may have resulted from soil movement into a nearby excavation pit, possibly due to insufficient depth of steel sheet piles used to retain soil in soft ground conditions.

He warned that construction near roads built on soft clay layers requires robust earth-retaining systems to prevent soil displacement, citing a major sinkhole incident on Samsen Road last September linked to underground rail construction.

Meanwhile, investigations into the Nakhon Ratchasima crane collapse are continuing. Provincial health authorities reported 30 confirmed deaths, with 16 injured patients still receiving treatment at hospitals. Nineteen bodies have been released to families for funeral rites.

Police have questioned engineers and machinery personnel from ITD as part of the investigation, with no charges filed so far.

Authorities said forensic experts are examining whether the accident was caused by negligence or equipment failure, noting that cranes do not collapse "without cause".