A Turkish Cypriot minister has faced fresh calls to quit after experts said that flaws in the redesign of a major highway – which took place under his watch – contributed to the deaths of four people during violent storms last month.

Günay Kandaz, Gaye Soyutok, Tolga Bekçi and Ahmet Kılıç – aged 18 to 23 – lost their lives when the car they were travelling in was swept off a tight bend on the mountain section of the Lefkoşa-Girne dual carriageway by a raging torrent on 5 December, 2018.

The floods, the worst seen for years, also wreaked havoc in the Girne region of the Turkish Republic of Northern Cyprus.

A total of 143 vehicles, 93 roads and walls, contents from 90 homes, and 12 buildings were damaged while dozens of people had to be moved to temporary shelter.

Reports into the disaster – commissioned from the Union of Cyprus Turkish Engineers and Architects Chambers (KTMMOB) by Prime Minister Tufan Erhürman – said that changes to a watercourse, combined with “inadequate” culverts that had become blocked by debris, meant that floodwaters flowed over the Ciklos section of the main Lefkoşa-Girne road rather than under it.

The route had been fully reopened to traffic just days earlier following months of resurfacing and design changes.

Work on the infrastructure project began on 23 February, 2018, three weeks after Public Works and Transport Minister Tolga Atakan, a People’s Party (HP) MP, was appointed to his post under a new four-party coalition.

Those who had authorised and implemented the alterations would be “held responsible”, Deputy Prime Minister and HP leader Kudret Özersay was quoted as saying.

Dr Erhürman, announcing the main findings of the independent investigation at a joint press conference late last week with Dr Özersay and KTMMOB officials, said that the amount of rainfall recorded on the night of the tragedy had been the “second highest” in North Cyprus since 1975.

He repeated warnings made last month that those found to have contributed to the floods by bu ilding on dry stream beds and diverting the natural flow of water would face legal action. The PM also backed calls for a “river catchment areas plan” that would include regular inspections and clean-ups of riverbed areas.

Civil Engineers’ Chamber head Gürkan Yağcıoğlu said that the construction of the present water diversion channels in the Ciklos area appeared to be “dangerous”.

The works had not been signed off by experts in his organisation “as required by law”, he added, while crash barriers at the site were believed to be “below standard”.

Mr Atakan, responding to the findings during a BRT TV interview, said that “no infrastructure would have been able to cope” with the level of rain.

The “filling”of stream beds “since the 1980s” and the addition of a second lane on the Ciklos bend had “contributed to making the scale of the disaster worse”, he claimed.

The section of the road in question was constructed by a firm from Turkey and financed by the Turkish state, Mr Atakan said, emphasising that work on the project had started “shortly after he assumed office”.

“The engineer responsible for the construction project has been contacted and an investigation is currently underway,” he added.

Mr Atakan’s defence failed to satisfy opposition MPs, including one of his predecessors Hamza Ersan Saner of the main opposition National Unity Party UBP), who served as Transport Minister between 2010 and 2013. Saner took part in a protest on Wednesday morning near the site of the flood deaths, standing alongside demonstrators waving placards that called on the government to resign.

Fellow UBP politician Kemal Dürüst, the Transport Minister between 2016 and 2018 who signed off on the Lefkoşa-Girne Highway Project, was notable by his absence.

The protest was led by main opposition National Unity Party UBP leader Ersin Tatar, who paid his respects to the victims and said he “shared the pain” of their families. He told reporters that while he had not wanted to “play politics over the suffering”, the time had come for resignations in the light of the report findings and investigations by the police.

“We need to take these matters more seriously and be more careful so that such an incident can never happen again,” he stressed.

His comments came after Mr Saner called on Mr Atakan to step down during a debate in Parliament on Wednesday.