By Jill McGivering BBC South Asia correspondent

Bhutan's Health Minister, Sangay Ngedup, says he raised almost $18 million from a recent publicity walk through the Himalayas.

The aim was to raise about $30m to set up what he describes as the world's first self-sustaining national health trust fund.

Although I did a lot of practice walks before the main walk, it was really not adequate Sangay Ngedup Health Minister

Speaking to the BBC in the Bhutanese capital, Thimpu, he said the walk had been a great success and despite health problems and dangers along the way, he would do it again if necessary.

The minister braved wild animals, high altitudes and some of the most remote terrain in the world during his gruelling 16-day trek.

Target

The idea is that interest from the fund pays for a nationwide immunisation programme and essential medicine.

The minister says the public response was very positive, and thousands of people joined him along the way to show support.

Of the cash raised so far, about 70% he said, had come from local people.

But he admitted the walk had been physically tougher than he had expected.

"Although I did a lot of practice walks before the main walk, it was really not adequate, because there was climatic variations," he said.

"There were variations in terms of elevation and, also, one was never really prepared to have any physical ailments, such as diarrhoea, which really pull you down physically.

"We used to get up at 2.30 in the morning to prepare for the day."

Poverty

The government now wants international agencies to respond to help them meet their target.

The scheme is a pioneering model, they say, which could be replicated in other small countries.

Bhutan is a tiny kingdom with a population of less than 700,000 people.

In recent years, it has made cautious moves towards political democracy and also towards greater interaction with the outside world.

It is still a mostly rural population with minimal development, and finding innovative ways of alleviating poverty is high on the government's agenda.