Family members of 74-year-old Singh spent about 30 minutes performing the final rites according to Sikh religion for him after the hearse reached the Batu Gantong crematorium.
They had to make repeated pleas to the public to move away from the casket.
Earlier, thousands of people lined the streets of George town to witness the funeral procession. A convoy of 100 superbikers led Singh's hearse procession.
The voluntary patrol unit members set up by the Penang Government cleared the crowd for the hearse to pass.
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Several people waved giant DAP flags at the entrance.
Penang Chief Minister Lim Guan Eng together with other party leaders lay the Penang flag on the coffin.
A small white DAP flag was placed on the casket.
Singh's political career began in 1970 when he joined the DAP. He won a seat in the Kedah State Legislative Assembly in 1974. He was first elected to parliament in 1978 as the representative for Jelutong, Penang, and held the seat for more than 20 years until losing it in 1999.
Singh returned to parliament after he won in the 2008 general election. He was till recently the Chairman of the opposition DAP party.