Key North-South Corridor works producing most noise, dust to be completed by end-2027: Jeffrey Siow

SINGAPORE – Most major structural works for the North-South Corridor (NSC) that create most of the noise and dust will be completed by the end of 2027, said Transport Minister Jeffrey Siow.

The completion of surface works will get priority, he added, so that surface conditions will start to improve from next year.

The Land Transport Authority will then reinstate roads, footpaths and other affected spaces from 2028. For instance, surface conditions for Lentor Avenue and Sembawang Road are expected to be back to normal by mid-2028, he said.

Siow was responding to questions in Parliament on Oct 6 on delay of the NSC. Denise Phua (Jalan Besar GRC) and Lee Hui Ying (Nee Soon GRC), for instance, asked what can be done for residents and businesses affected by the delay.

Siow said the authorities will be paying more attention to businesses along the construction route, including making it a priority to restore access routes for pedestrians when surface works are completed.

This is because changes to pedestrian routes or road access affect customer traffic for neighbourhood businesses.

LTA will also try to put in place more direct walking routes to shops and eateries and make it easier for customers to get to the shops.

Siow added that several businesses in Housing Board rental shops most affected by NSC construction works have been receiving rental rebates on a case-by-case basis, and HDB will continue to extend the rebates if there are grounds to do so.

As a general principle, the Government does not compensate stakeholders for project delays because that can add significant costs upfront to these projects, he said.

Jackson Lam (Nee Soon GRC), Lee Hong Chuang (Jurong-East Bukit Batok GRC) and Yip Hon Weng (Yio Chu Kang) also raised questions about the costs of the two-year delay to the completion of the NSC.

Siow said the delay is likely to result in a higher project cost but LTA is still assessing the extent of permissible claims by contract, and so it is unable to provide an updated project cost at this point. It will do so later.

He also touched on why more time is required to complete the 21.5km highway linking the northern towns to the city. He said: “The NSC is one of the most complex road projects we have undertaken in Singapore.”

It passes through densely built-up areas and bypasses major utilities, heavily used roads and even MRT lines, he added.

In some places, tunnelling works took place less than a metre away from the North-South Line and Circle Line, which are both in operation, said Siow.

The delay means that the NSC viaduct, which runs from Admiralty West to Lentor Avenue, will now open in stages from 2029, instead of 2027.

Meanwhile, the tunnel section from Lentor Avenue to East Coast Parkway will open in phases from 2031 instead of 2029.

On pre-construction soil investigations, he said such investigations are not exhaustive as they are done on a sampling basis using scanning tools and physical drilling in key areas.

Siow added that there are limits to what can be detected, especially when ground conditions are variable.

As excavation progressed, he said the actual conditions at several locations turned out to be different and more difficult than what was indicated in the soil investigations.

For example, in Gambas Avenue and Woodlands Avenue 8, harder rock was found at shallower depths than expected.

And in Novena, the issue was fractured rock and groundwater seeping through the cracks.

WP MP Louis Chua (Sengkang GRC) and Yip asked if soil investigations provide enough information on underground conditions and engineering risks.

Siow said LTA and its contractors tried different ways to resolve these challenges, including deploying more manpower and equipment, adjusting construction methods and changing the sequence of works.

LTA engineers studied all their options before concluding that compressing the programme further with these ground conditions would pose significant safety risks.

“This is not the trade-off that we should make,” Siow said.

As these works are taking place beside people’s homes, roads that are in use and operational MRT infrastructure, contractors will not rush the work if it puts workers, residents or commuters at risk, he added.

As for Yip’s question on why stakeholders were not alerted of the delay earlier, Siow said LTA made the announcement “as soon as practicable”.

Engineers needed to assess the situation, see how to continue project works, and do it safely. It was only when the works progressed that the engineers realised the risks were too great, and a decision was made to accept there will be a delay, he added.