Meanwhile, the National Disaster Management Authority on Sunday said that work is on to retrieve broken parts of the auger machine and start manual digging.
Till 6 pm, up to 44 metres of an escape pipe had been inserted into the debris of the collapsed stretch of the tunnel.
Night travel (7 pm to 6 am) has been banned along the Udumbanchola-Cheriyar stretch on the Munnar-Kumily state highway from Monday till further notice.
According to local residents, the landslide happened with an ear-splitting sound, and heavy water currents are still occurring in the area where the landslide occurred
The landslip caused due to flash flood at the Pandanmala hills near Mannarkkad on Friday evening.
As heavy rain continues to batter the area, all three shutters of the Kanjirappuzha dam have been raised by 70 cm.
In light of the incessant rain and waterlogging, a relief camp has been opened at Vellikulam School.
There were landslides at many spots on the Angamoozhy - Gavi road, the main road of the area, said officials.
With the dam being opened, water levels in Kakkad and Pampa rivers have risen.
As many as 120 people have died in rain-related incidents in the state this month.