Major slips have shut down the Napier-Gisborne railway north of Wairoa, including one where about 100 metres of track is suspended in mid-air.
The big washouts, including the one in the Kopuawhara-Beach Loop area, are raising fears KiwiRail will be forced to permanently close the line soon.
KiwiRail has previously threatened to mothball the track unless there is a dramatic improvement in freight traffic to offset losses of well over $2 million a year on the line.
It is one of four which Transport Minister Steven Joyce has said could be closed by the end of this year.
No decisions have yet been made in relation to the latest washouts which happened late last week, and yesterday KiwiRail spokeswoman Jenni Austin said it was hoped a report on the damage would be available by tomorrow.
Access to the area was difficult, but staff and engineers were moving in and out of the area where rain in March had been among the heaviest since Cyclone Bola, 24 years ago.
"Very much the next step is understanding the extent of the damage and the cost," she said.
There were "at least three significant washouts," she said, and added: "We've got to look at all of the damage. These alone will require major works, so we won't be running any trains on the line [between Wairoa and Gisborne] soon."
No trains were trapped on the Gisborne side, and the Wairoa-Napier section, itself closed last week by smaller washouts, can still be used, mainly for transporting logs.
Supporters of retaining the track had been hopeful increased traffic to and from Gisborne would save the line. From one-two trips a week it had increased to four in recent months transporting produce, mainly squash.
Ravensdown has been a significant user of services to Gisborne, but a spokesperson there were alternatives in road transport, and possibly coastal shipping.
It is another setback to access to Hawke's Bay and the East Coast with the Manawatu Gorge now closed more than seven months because of a major slip and the Waioeka Gorge closed more than three weeks.
Napier MP Chris Tremain, whose electorate includes Wairoa, who has worked to encourage business on to the line in the hope of saving it from the cut, and who was today heading north to discuss the Waioeka Gorge issue, was last night surprised to see images of the damage north of Wairoa.
"It's certainly a lot larger than I expected," he said.
Asked about fears that it could force the decision to close the line, he said: "I've certainly wanted to keep the line open, but within the parameters that KiwiRail and the Government have set. It has to be sustainable."