Mr Dhesi became Labour's MP for Slough in June, was recently accused of ignoring the plight of a British Sikh man who was arrested during his visit to India.
But the lawmaker vowed to continue working for the whole public "regardless of background, colour or creed" rather than focussing on just one community, according to a report by British tabloid, The Sun.
The abuse came after Mr Dhesi won the right to speak at Prime Minister's Questions and used the slot to ask about a rail link in his local area. Trolls said he should have asked about Jagtar Singh Johal, a Scottish activist who has arrested in India, the report said.
One troll wrote to the MP saying, "A Sikh British citizen is being tortured in Punjab and you're worried about rail. You have no response to that. You need a slap upside your head you fake Sikh!"
Dhesi reacted with fury and pointed out that he has repeatedly worked on Mr Johal's case.
"It's hard enough serving as an MP without having to face constant abuse from various quarters (whether that's the far-right/extremists/others who feel that I'm only interested in 'my community's issues' or those from within my 'own' community who feel I don't do enough)," he wrote on Facebook.
"When people resort to abuse, they are actually doing a disservice to their own cause. I will do what I genuinely feel is right, rather than be forced by anybody to follow their priorities or way of thinking. "I am not merely a Sikh MP/representative speaking solely on Sikh issues," Mr Dhesi added.