Pedestrians at a zebra crossing on the busy Mombasa Road. The expressway, once completed, is expected to reduce travel time between Nairobi and Mombasa from the current 10 hours to four hours. [Edward Kiplimo, Standard.]

Kenya’s second-biggest infrastructure project since independence five decades ago, a $3.5 billion (Sh350 billion) inter-city expressway, will be delayed amid concerns by lawmakers that East Africa’s largest economy is taking on too much debt, the company building it said.

While Kenya is ramping up construction of much-needed infrastructure to underpin economic growth, the cost of the mega projects, mostly financed by Chinese loans, has stirred concern that the debt is unsustainable for the $71 billion (Sh7.1 trillion) economy.

The nation’s debt could rise to 58 per cent of gross domestic product by the end of June, from 40.6 per cent in the 2011-12 fiscal year, according to World Bank estimates.

Construction of the 473km four-lane highway between the capital, Nairobi, and the second-biggest city, Mombasa, will be undertaken by San Francisco-based Bechtel Group Inc., which has arranged commercial loans for Kenya to undertake the project. The country will not seek concessional financing or a public-private partnership, according to the company.

The Kenya National Highways Authority wasn’t aware of any delay, public relations officer Charles Njogu said by phone. “The agreement has, however, to be scrutinised by lawmakers because of its size,” he said. Transport and Infrastructure Secretary James Macharia didn’t answer calls to his mobile phone nor respond to a text message seeking comment.

 Central bank Governor Patrick Njoroge told lawmakers Thursday that the country needs to move into “non-debt creating ways” of financing projects, citing the Bechtel project.

There’s “less and less headroom for additional borrowing, given the currency concerns, and that room is narrowing,” he said.

The financing arrangements for the toll road are now expected to be in place by end-June, the initial sod-turning target, and construction work will now begin in the second half of the year, said Andrew Patterson, Bechtel’s regional president for Africa.

“This is looking to be slipping,” he said in emailed responses to questions on Monday. “The debt level is a big concern and we are working to find the right balance with Treasury in regards to the financing.” Kenya’s biggest infrastructure project since independence from Britain in 1963 is an $8.7 billion (Sh870 billion) standard-gauge railway from Mombasa to the Ugandan border that’s being built under China’s flagship Belt and Road program. The first phase of the line that replaces a parallel century-old link built during the colonial era is already operational.

Bechtel said in December it was supporting the Kenyan government in negotiations with the US Export-Import Bank, the Overseas Private Investment Corp and UK Export Finance to finance the dual carriageway.