Washington, Mar 25 (IANS): The first crewed flight of Boeing's CST-100 Starliner has been delayed till May, NASA has announced.

It was previously scheduled for late April, but has reportedly been delayed due to last-minute tests and technical debates.

In a tweet, Kathy Lueders, NASA Associate Administrator of Space Operations, said the CST-100 Starliner will now launch after Axiom Mission 2.

While the dates are yet to be announced, she said it is likely to blast off to space in May, this year.

"We're adjusting the @Space_Station schedule including the launch date for our Boeing Crew Flight Test as teams assess readiness and complete verification work," Lueders said on Twitter.

"CFT now will launch following Axiom Mission 2 for optimised station operations," she added.

In April last year, Axiom Space became the first-ever private mission to visit the International Space Station (ISS).

The American private space habitat company's Axiom Mission 1 (Ax-1) with 4-member crew spent about 17 days in space.

The Ax-2 is likely to fly to space in May to expand robust scientific research, biomanufacturing, and technology demonstrations in low-Earth orbit, the company said.

"Target launch dates for Ax-2, still planned in early May, and Starliner will be shared soon. We'll plan a media update after we have the space station schedule set. As always, we will fly when we are ready," Lueders said on Twitter.

Boeing had signed a contract with NASA's Commercial Crew Programme to fly operational missions to and from the space station with Starliner in 2014.

It had last year conducted two tests of uncrewed flights to space.