The assets of at least three union ministers have increased since they assumed office five months ago, a joint statement by the National Election Watch and Association of Democratic Reforms said Friday.

The highest increase in assets in five months was shown by Railway Minister D.V. Sadananda Gowda.

"His assets have shown an increase of Rs.10.46 crores, from Rs.9.88 crores as declared in Lok Sabha 2014 elections to Rs.20.35 crores in the 2014 declarations of the Union Council of Ministers to the PMO," the statement said.

Minister of State for Heavy Industries and Public Enterprises Radhakrishnan P was a distant second. His assets showed an increase of Rs.2.98 crores, while Finance Minister Arun Jaitley showed an increase of Rs.1.01 crores.

The watchdogs said 41 or 91 percent of the union ministers are crorepatis as per their declarations to the Prime Minister's Office.

Jaitely was the richest at Rs.114.03 crore, followed by Harsimrat Kaur Badal at Rs.108.31 crores and Piyush Goyal at Rs. 94.66 crores.

The statement said that 16 ministers have shown a decrease in assets.

"External Affairs Minister Sushma Swaraj showed a decrease of Rs.3.89 crores (from Rs.17.55 crores declared in the 2014 Lok Sabha elections). She is followed by Minister of State for Development of North Eastern Region V.K. Singh who declared a decrease of Rs.3.13 crores (from 4.11 crores declared in the 2014 Lok Sabha elections). He is followed by Health Minister Harsh Vardhan who declared a decrease of Rs.1.28 crores," the statement said.

The statement said that upon analysis it was found that the cause of changes in assets was largely due to the lack of any standardised format for ministers' asset declarations.

"Many ministers have not given the value of many assets declared. Not declaring the value of assets in the ministers' declaration is akin to not making a disclosure at all," the statement said.