India's government has faced mockery on social media for tweeting an apparently doctored photo of its image-conscious prime minister surveying the flood-hit southern state of Tamil Nadu.

Narendra Modi tweeted an image of himself looking out of a helicopter window as he flew over the devastated area on Thursday, saying he was "pained by the devastation" he had seen.

The scene through the window was barely visible in the posted photo.

However, when the government's press department later tweeted what appeared to be the same image, the view through the window was sharp and clearly showed flooding.

The department later deleted that tweet, but not before thousands of followers had snatched up screen grabs of the apparently manipulated image.

The photograph sparked a slew of Internet memes, including one showing a pensive Modi looking through the helicopter window as Superman flies by.

"Very silly of @PIB-India to photo-shop @PMOIndia aerial survey of Chennai," tweeted Prashanth Rao, referring to the state capital.

"Worst photoshop ever!" tweeted "Wilbur Sargunaraj." "Why does our PM need false and exaggerated propaganda???"

The Press Information Bureau (PIB) said later that two pictures had been accidentally merged in an "error of judgement."

"PIB regrets the release of the above mentioned picture," the bureau said in a released statement.

Modi traveled to Tamil Nadu on Thursday to survey the damage from weeks of flooding that has killed 269 people.

Taking office in May 2014, India's 15th prime minister is a prolific tweeter with more than 16 million followers.