A failure to count the members of pop group SMAP and their entourage as they boarded an All Nippon Airways plane caused a 48-minute delay on the tarmac in Sapporo, an ANA spokeswoman said Friday, laying the blame to a procedural error.

The Boeing 777, bound for Haneda Airport with 503 passengers, returned from the taxiway to the gate at around 12.30 p.m. on Thursday, when it became apparent that two members of the SMAP party were not on board, according to the spokeswoman, who asked not to be named.

"Seventeen seats had been reserved for SMAP and their staff, but only 15 boarded on the day," she said.

"The plane returned to the gate so that the doors could be opened and the number of passengers could be checked," she said.

"SMAP and their staff went through a different boarding process from other passengers to avoid chaos, as there were many SMAP fans at the gate. But that is unrelated to this incident," she said.