The government is set to postpone its plan to extend the Hokkaido Shinkansen line to Sapporo by the spring of 2031 amid delays in construction and the city's plan to abandon its bid to host the 2030 Winter Olympics, government sources said Saturday.

The transport ministry and Hokkaido Railway (JR Hokkaido) will arrange a new deadline, but the 212-kilometer extension project between Shin-Hakodate-Hokuto and Sapporo still faces a labor shortage in the construction sector, which is expected to worsen when Japan introduces new overtime regulations in 2024.

The move comes as a part of the construction work is already projected to be up to four years behind schedule due to problems, including a massive rock obstructing tunnel construction.

The bullet train to Sapporo would not have been realized in time for the Olympics even if the construction had progressed as scheduled.

The ministry has so far upheld the 2031 deadline, wary of announcing a postponement too quickly in case Sapporo became the host city for the Games and an early completion could be driven forward, according to a senior ministry official.

Sources familiar with the matter said Friday that Sapporo is set to abandon its bid to host the 2030 Winter Olympics and will instead aim to stage the Games in 2034 or later.

The government approved the extension of the bullet train line in 2012, with the cost estimated at ¥1.67 trillion. The estimate soared to ¥2.32 trillion last year due to rising material costs.