Spending cuts at the infrastructure ministry are threatening plans for a metro connection from Amsterdam to Schiphol which will in turn scupper the expansion of international rail services, state-owned railway company NS has warned.

The extension of the Noord/Zuid metro line, which would allow people to take the underground to the airport, would reduce the number of airport train services and create more space on the network for international services, regional rail operator chief Harro Homan told broadcaster NOS.

International trains have been widely touted as an alternative to short haul flights, and several international train companies as well as NS are jostling for space.

The metro line currently ends at station Zuid in the Zuidas business district, which is also the future location for international train services.

“If the money isn’t made available, the plans for more international services will become uncertain,” Homan said. The shortfall in funding is currently some €1.8 bn, Homan told the broadcaster.

At the end of December last year, the Parool reported that Amsterdam city council was threatening to stop putting money into another massive infrastructure project – to put part of the A10 ring road at Zuidas into a tunnel – if the state did not fund the metro extension.

The cost of the Zuidasdok project was put at €5.5 bn in 2022 – the third price hike since it was first mooted. But at the end of last year, infrastructure ministry said the actual cost is likely to be €600 million to €800 million more.