"The BJP appeals to party karyakartas not to politicise Uttarakhand tragedy. Even if you are instigated by others stay calm and composed," Singh said on Twitter.
His remarks come against the backdrop of claims that Modi had helped evacuate 15,000 Gujaratis stranded in flood- affected Uttarakhand in two days.
This had led to attacks and counter-attacks between supporters- including those on social media sites- of Modi and Gandhi.
"The BJP today dispatched 8 truckload of relief material and Rs 56,06,994 in cash as symbolic gesture from Lucknow to Uttarakhand. The BJP has also directed all state units not to flag off relief material as it hurts the human sensibilities," Singh said.
He clarified that contrary to certain media reports, there was no flagging off at Lucknow.
"The relief was simply dispatched to the flood affected people," Singh said.