The Supreme Court handed down an 18-month prison sentence and 40 million rupees ($550,000) fine to Chiranjibi Wagle, a senior leader of the Nepali Congress party who held a series of ministerial portfolios.

Wagle, 58, was minister for information and communications, planning and works, land reforms and home affairs between 1990 and 2002.

"The Supreme Court verdict is the first in which a former minister has been sent to jail for corruption. It will be immediately implemented," court spokesman Hemant Rawal said.

The ruling on Wednesday rejected an appeal filed by Wagle after he was convicted in 2004.

He repeatedly denied charges of illegally amassing properties and transferring them into the ownership of his son, daughter-in-law and other family members.

Nepal, one of the poorest countries in the world, was ranked 146th out of 178th in Transparency International's 2010 corruption perception index.