The RMT has promised to maintain a policy of "extreme vigilance" over safety and security issues around the Night Tube ahead of the 24-hour service's launch tomorrow evening (19 August).
The union also stressed that it has supported the project, which will initially be rolled out across the Central and Victoria line on the London Underground, since the programme was first announced in 2014.
The clarification comes after a series of industrial disputes between management and Underground unions, including the RMT, TSSA, Unite and Aslef, over pay and work conditions caused the service's initial launch of September 2015 to be delayed.
"The truth is that it is not politicians and their top officials who will deliver a Night Tube for London it is the cleaners, station staff, drivers, engineers and all the other grades working anti-social hours who will be transforming London into a 24-hour City and they deserve all the praise and the credit," said Mick Cash, general secretary of the RMT.
"RMT will be maintaining a policy of 'extreme vigilance' with our reps monitoring issues like safety, security and the impact on staff of running services round the clock.
"The union will also continue to resist any attempts to deliver Night Tube on the cheap. Huge logistical challenges in areas like safety, maintenance and engineering will remain under close scrutiny by the union."
The Night Tube, which is expected to support 2,000 permanent jobs and boost the economy by £360m, will later launch on the Northern, Piccadilly and Jubilee lines in the autumn. Cash claimed he was "conscious of a range of problems" with the second tranche of services.
"It is essential that those issues are dealt with through the negotiating machinery and that procedures aren't dodged in order to hit arbitrary deadlines," he added, without identifying specific disputes.
Steve Griffiths, chief operating officer for London Underground, said: "The Night Tube will make life easier for everyone, particularly night-shift workers getting to and from work.
"It will cut journey times, create jobs and boost the economy. The safety and security of everyone working on or using the Night Tube is our top priority. Our staff are highly trained and experienced to deliver the new services, every station will be fully staffed and controlled, and we have invested in a visible presence of 100 police officers and additional police community support officers to assist customers.
"The start of Night Tube services on the Jubilee, Northern and Piccadilly lines will follow in separate phases later in the autumn as new Tube drivers complete their training and final preparations are made."
Mayor of London Saidq Khan has committed £3.4m ($4.4m) extra funding for the additional police officers to patrol the Night Tube, while TfL has launched eight new bus routes to complement the 24-hour service.
"The safety and security of Londoners is vital, and it's why we've invested in new police officers on the Tube and it's why we're bringing in these brand new 24-hour bus services," Khan stated.