AHMEDABAD, India (AFP) - A pilot who is trying to make history by flying a solar-powered plane around the world launched an angry attack on Indian bureaucracy on Wednesday after a lengthy hold-up in Prime Minister Narendra Modi's home state.

Bertrand Piccard, one of the two Swiss pilots of Solar Impulse 2, said he and his team had been frustrated by delays over paperwork in Ahmedabad city in the western state of Gujarat.

The plane landed in Ahmedabad last Tuesday from the Omani capital Muscat after completing an initial sea crossing in its epic bid to become the first plane to fly around the world solely powered by the sun.

The single seater had been due to leave on Sunday for a short flight to the Hindu holy city of Varanasi before heading onto neighbouring Myanmar.

But the plane, flown by co-pilot Andre Borschberg, could only leave on Wednesday morning after delays blamed on bad weather, while Piccard's support team remained stuck at Ahmedabad airport hours after takeoff.

"The delay is (because of) of administration, papers, stamps," Piccard told reporters at Ahmedabad airport.

"I'm not here to accuse anybody. I just say that since the last five days we are trying to get all the stamps and every day (they) say tomorrow," said Piccard.

"Since five days we are desperate to get all the stamps and we still have stamps missing." Piccard's team must arrive in Varanasi ahead of Solar Impulse 2 to coordinate its landing scheduled for around 1530 GMT.

The team posted pictures on Twitter of themselves at the airport looking anxious and miserable, before finally getting the go-ahead to leave hours later. Another picture shows a smiling Piccard holding up his passport with stamps in it.

Piccard's comments risk embarrassing Modi, who has vowed to cut bureaucratic red tape in promised reforms to revive India's economy after storming to power at general elections last May.

Modi, who was the chief minister of Gujarat before becoming premier, wants to attract more foreign companies who have long complained of encountering bureaucratic nightmares in India.

Modi supporters have often touted Gujarat's business-friendly policies as a model for success which should be replicated nationally.

Kiran Mazumadar Shaw, chief of Indian biotechnology company Biocon, took a swipe at Modi's government following the pilot's tirade.

"Hope (the government) heard the solar plane's pilot commenting on bureaucratic delays n cumbersome paperwork...Red tape and petty officialdom are stalling progress," she wrote on Twitter.

The team behind Solar Impulse 2, which has more than 17,000 solar cells built into its wings, hopes to promote green energy with the circumnavigation attempt.

Ridiculed by the aviation industry when it was first unveiled, the venture has since been hailed by UN chief Ban Ki-moon.

Muscat was the first of 12 planned stops on the plane's journey around the world from Abu Dhabi, with a total flight time of around 25 days spread over five months.

The sea legs pose the greatest challenge for the Solar Impulse team as any loss of power over the water would leave the pilot no alternative but to bail out and await rescue by boat.

The longest single leg will see one of them fly solo non-stop for five days and nights across the Pacific from Nanjing, China, to Hawaii - a distance of 8,500km.

The plane's maiden leg last Monday took co-pilot Andre Borschberg 13 hours and two minutes, while Piccard's flight to Ahmedabad of 1,468 kilometres was hailed as the longest point-to-point distance flown by a solar-powered plane.

Borschberg, the CEO and co-founder of Solar Impluse, set the previous record when he flew 1,386km across the United States.