"Today we conducted an aerial survey of flood affected areas with the Chief Minister and I reached the conclusion that the situation is very serious in Kerala due to floods," he said.
He assured the state government of all help from the Centre to meet the challenges posed by the unprecedented floods in Kerala.
"An unprecedented flood situation is facing the state of Kerala. It is unprecedented because never before in the history of independent India, Kerala had to witness such massive floods," he wrote on Twitter.
"And I would like to assure the state government that all sorts of support will be provided by the central government to meet the challenges of the flood situation," he said.
The Central government stands firmly with the state government in this situation, the union minister said.
"These floods have caused massive damage to the crops like paddy, banana plantations and to the cash crops like spices. It has caused severe damage to infrastructure like roads, power lines and individual property.
"I must say that the entire nation is firmly standing by the people of Kerala at this difficult hour. The Centre is closely monitoring the situation here and providing all possible assistance to Kerala. We will leave no stone unturned to mitigate this unprecedented disaster," the home minister said.
Singh said three teams of NDRF were pre-positioned in Kerala during the current Monsoon season while eleven more NDRF teams have been deployed in the state taking the total number of NDRF teams to 14.
"If needed we will press in additional teams would be pressed into service," he said.
"I understand the suffering of the people of Kerala due to this unprecedented crisis. Since assessment of damages will take some time, I hereby announce immediate relief of an additional Rs 100 crores," he said in a series of tweets.
"I would like to appeal all political parties, social & cultural organisations to join hands with the state government in mitigating the sufferings of the people of Kerala, at this critical hour."
Earlier, Singh, on his arrival here, held a brief meeting with Vijayan, the Revenue Minister, Agriculture Minister V S Sunil Kumar,Water Resources Minister Mathew T Thomas and Chief Secretary Tom Jose at Cochin International Airport.
The Minister made an aerial survey of areas affected by landslides and rains in Idukki and Ernakulam districts.
He was accompanied by Vijayan, Kannanthanam, Chandrasekharan and Additional Chief Secretary P H Kurian.
After a brief lull, rains started lashing several parts of Kerala since this morning, posing problems to relief work by multiple agencies in flood and landslide hit regions.
However, water level in Idukki and Idamalayar dams reduced, bringing some relief, with authorities saying there was no need for people living downstream to panic.
No fresh casualties were reported since yesterday and the toll in the rain-related incidents since the current monsoon fury from August 8 stood at 37, officials said.
More than 60,000 people have been accommodated in relief camps set up in different areas, including in Wayand, where over 14,000 people had been sheltered.
Ten columns of Army, a unit of Madras Regiment along with personnel of Navy, Air Force and NDRF are engaged in relief and rescue work in badly-hit districts, including Kozhikode, Idukki, Malappuram, Kannur and Wayanad, Defence sources said.
Water level in Idukki dam, the biggest arch dam in Asia, which was opened after a 26 year gap, marginally declined to 2399.16 feet at 10 AM today, after hovering close to its maximum of 2,403 feet in the past few days, officials said.
Around 1,500 houses were damaged partially and 101 have been destroyed completely in rain fury in Kerala in the last few days, according to the disaster control room officials in Thiruvananthapuram.
(With inputs from PTI)