A powerful earthquake has hit a remote, impoverished part of western Pakistan killing at least 45 people.

Tremors were felt as far away as the Indian capital of New Delhi, hundreds of kilometres to the east, as well as the port city of Karachi in Pakistan.

The United States Geological Survey said a 7.8 magnitude quake had struck over 230km southeast of Dalbandin in Pakistan's earthquake-prone province of Baluchistan, which borders Iran.

Officials said some areas appeared to be badly damaged in the regional capital of Quetta.

However, it was hard to assess the impact quickly because the locations were so remote.

The earthquake was so powerful that it caused the seabed to rise and create a small, mountain-like island about 600 metres off Pakistan's Gwadar coastline in the Arabian Sea.

Television channels showed images of a stretch of rocky terrain rising above the sea level, with a crowd of bewildered people gathering on the shore to witness the phenomenon.

Officials said scores of mud houses were destroyed by aftershocks in the thinly populated mountainous area near the quake epicentre.

Local television reported that helicopters carrying relief supplies had been dispatched to the affected area.

The army said it had deployed 200 troops to help deal with the disaster.