Tottenham have apologised to fans for the delay in opening their new stadium, but say it was "unavoidable" because they could not "compromise safety".
Spurs were expected to play their first game at their new ground on 15 September against Liverpool, but that match has been switched to Wembley.
They have also moved their following home game - against Cardiff on 6 October - to the national stadium.
The club have offered supporters full refunds for the "inconvenience".
BBC Sport understands the club had been in discussion with Uefa regarding a potential delay, even before Monday's announcement.
At least one Champions League group fixture will be affected depending on the draw, which takes place in Monaco on 30 August.
That may mean the team open their European campaign at Wembley, or ask for their first group fixtures to be played away from home. There is no indication yet that such a request would be approved.
A club statement read: "Delays are common, certainly for builds of this size and complexity, however we are hugely frustrated that this has occurred at such a late stage.
"Whilst we would have been able to mitigate other areas, we simply cannot compromise safety. This decision was unavoidable."
An NFL fixture between Seattle Seahawks and Oakland Raiders, scheduled to be hosted on 14 October, will now also take place at Wembley instead of Spurs' new 62,062-seat arena, built on the site of their old White Hart Lane ground.
The venue for the club's Premier League game against Manchester City on 28 October is yet to be confirmed.
Spurs had already agreed with the Premier League to play their first home game of the season, which is against Fulham on Saturday, at Wembley.
They exercised an option to use the national stadium for other fixtures "at the end of last year as a sensible back-up given the nature of construction".