Torrential monsoon rain has brought transport across much of Nepal to a standstill, blocking major highways at more than a dozen locations, stranding travellers and prompting authorities to close key road links to the capital as forecasters warned of more downpours in the coming days.

The Department of Roads said landslides and flooding had disrupted traffic at at least 15 locations on the country's strategic highway network, including the Narayangadh–Muglin Highway, the principal road artery linking Kathmandu with southern and western Nepal.

The Chitwan District Administration Office on Monday suspended all vehicle movement along the Narayangadh–Muglin section until further notice after continuous rainfall triggered landslides at multiple points along the highway.

Authorities advised travellers not to leave Kathmandu Valley, while those travelling from the western districts towards the capital were asked not to proceed beyond Chitwan.

"The road has become unsafe due to continuous heavy rainfall and landslides," the administration said in an emergency notice, urging travellers to postpone journeys unless absolutely necessary.

The Road Division Office in Chitwan said falling boulders at Tuin Khola and debris flows at Seti Dobhan had blocked both lanes of the highway, while persistent rainfall was preventing crews from clearing the slides.

Motorists stranded by the closures were urged to move their vehicles to safe locations and monitor official updates before resuming travel.

Authorities also suspended traffic on two alternative highways connecting Kathmandu Valley with Hetauda after landslides and swollen rivers rendered the roads hazardous.

The Makwanpur District Administration Office closed the Hetauda–Tingan–Bagmati–Lalitpur road indefinitely and temporarily halted traffic on the Hetauda–Bhaise–Bhimphedi–Sisneri–Kathmandu route, citing concerns over passenger safety.

The widespread disruption comes after a weekend of intense rainfall that washed away roads and bridges, cut off access to the popular trekking village of Ghandruk, stranded hundreds of tourists and forced four hydropower plants along the Modi River to suspend electricity generation.

Nepal's Department of Hydrology and Meteorology said heavy rain accompanied by thunderstorms would continue across much of the country through Wednesday, with isolated areas of Koshi Province expected to receive heavy to very heavy rainfall.

The agency forecast widespread rain across Koshi, Madhesh, Bagmati, Gandaki and Lumbini provinces, while warning of a heightened risk of floods, landslides, debris flows and river inundation.

The National Disaster Risk Reduction and Management Authority has urged residents living along rivers and in landslide-prone areas to remain vigilant, avoid unnecessary travel and follow official weather advisories.

The heavy rainfall marks a sharp turnaround after weeks of concern over a delayed and forecast weaker-than-normal monsoon. The monsoon arrived in Nepal several days later than usual, raising fears of poor paddy transplantation and water shortages, but rainfall has intensified in recent days, with some areas recording more than 150 millimetres (six inches) in a single day.

Nepal's annual monsoon, which typically lasts from June to September, frequently triggers floods and landslides that kill dozens of people and damage roads, hydropower infrastructure and settlements each year. This week's downpours have once again exposed the country's vulnerability, with mobility across large parts of Nepal severely disrupted as emergency agencies brace for further rain.