KATHMANDU: CPN-UML Chairman and Parliamentary Party leader KP Sharma Oli is heading to Bangkok for a medical trip.

According to Surya Thapa, the deputy chief of the party's publicity department, Oli is going to the Thai capital for a regular health check-up.

Oli is scheduled to board a regular Thai Airways flight tomorrow afternoon.

The top leader of the second largest party, Oli has been considered as the strongest candidate for the post of Prime Minister when Sushil Koirala steps down after the promulgation of new constitution as per an understanding among the Nepali Congress and CPN-UML while forming the government in the Nepali Congress President Koirala's leadership.

Oli, who had underwent a successful kidney transplant in 2007, suffers from multiple problems and keeps on visiting hospitals in foreign lands as he falls sick time and again.

In September last year, he had visited New Delhi for medical tests. A few weeks after he returned from a medical trip to Bangkok for the party's General Convention that elected him as the party's top leader, Oli went to Singapore for the treatment of his swollen hands last July at the National University Hospital last July.

He was flown to Bangkok on an air ambulance on April 30 the same year. The government had borne his medical expenses then. He had stayed in Bangkok for a month and received treatment at the Bumrungrad International Hospital for systemic infection and cryptococcal meningitis.

Earlier from March 2 to April 16 last year, he received treatment in New Delhi.