"We have held extensive discussions on matters pertaining to cross border crimes and fake currency among other things during the meeting," Singh told journalists just before leaving for New Delhi.
"We have also discussed about developing a mechanism to control these crimes," he said.
Singh was on a three-day visit to Nepal to attend the 6th SAARC Interior/Home Ministers' meeting.
The notorious influx of counterfeit currency notes threatens India's economy. India has from time-to-time drawn the attention of Nepal government towards the blooming currency rackets there.
On a question about terrorism, he said: "We will face all kinds of challenges related terrorism with full strength."
Home Minister Singh said peace, stability and prosperity in Nepal is crucial for India's interests.
"India realises that when there is peace, prosperity and stability in Nepal, only then we can have peace, prosperity and stability in our country," he said.
Singh also assured all kinds of assistance to Nepal for its development.
He said talks on the pending extradition treaty will continue with Nepal. "We haven't reached any conclusion yet, but I am confident that it will be fruitful."
Besides attending the SAARC meet, Singh met Nepal's President Ram Baran Yadav, Prime Minister Sushil Koirala and his Nepalese counterpart Bamdev Gautam.
He also held consultations with senior political leaders of the ruling and opposition parties.
"I felt after meeting people here that Prime Minister Narendra Modi's visit to Nepal has had a very positive impact on common people," he said.
Singh lauded signing of a pact between Nepalese government and GMR Energy Group to develop the 900 MW Upper Karnali hydropower project and assured that more investments will pour-in from India after the landmark agreement.