KiwiRail says any replacement overbridge across the Wanganui-Marton rail line in Wanganui East will need to meet a number of requirements.
The state-owned enterprise is responsible for the country's rail network and, while it was not aware of suggestions to close the Wakefield St overbridge, said it would be watching developments.
The ageing wooden bridge, built in the early 1950s using secondhand timber, already has speed and weight restrictions applied to it - but now rotting timberwork means it has to either be replaced or be closed.
The closure option has been included in the Wanganui District Council's draft Annual Plan with council saying it cannot afford the $1.8 million estimated to replace the bridge,
That idea has been met with public outcry, especially from Wanganui East residents directly affected by closing the bridge.