The manager said: "It's a hotel room, what should I say?' We do not give comments on guests' behaviour."
One of the workers, who works locally but didn't wish to be named, told The Sun: 'It's obviously not the kind of thing you see every day.
"We couldn't really believe it.
"It was taken last week and since Monday has been going round to all the workers on WhatsApp who work in the area."
The footage was the talk of the office as colleagues became distracted at their desks and meetings were interrupted.
One of the workers thought the couple had done it on purpose as they must have known they were being watched.
Motel One is a "budget designer hotel" and has 291 rooms starting at £98 (NZ$166) a night.
A spokeswoman for the City of London Police told MailOnline the incident had not been reported to them.
The incident brings to mind a similar occassion in 2015 when Chrstchurch employees of insurance firm Marsh Ltd unwittingly put on a public sex show for patrons of a pub across the street from the glass-fronted building after leaving the lights on one Friday night.