David Ayer wanted to make 'Gotham City Sirens' for his daughter.

The filmmaker helmed the 2016 villain-focused movie 'Suicide Squad' - which featured Harley Quinn, one of the 'Sirens' - and Ayer reportedly was eyed for the upcoming sequel but decided to focus his attention on the female-orientated movie.

Speaking to Den of Geek, the filmmaker said: ''It's a story about three fantastic women who're trying to find their way in the world, and realise that they have more power together than they do individually.

''I have daughters and I want to create something that might be able to help them get along in the world a little bit.''

Margot Robbie - who is also an executive producer on the project - will reprise her role as sexy, psychotic supervillain Harley in the new movie, which will focus on the women from the DC comics world.

In the recent comic series, which the movie will be based on, Catwoman and Poison Ivy featured alongside Harley and could appear in the upcoming film.

'Sherlock Holmes 3' writer Geneva Robertson-Dworet is penning the script.

In September, Robbie was reported to have signed a ''first-look'' deal with Warner Bros. to produce the Harley spin-off film.

She is said to have fallen in love with the character after portraying her in 'Suicide Squad'.

It's not known whether Quinn's dangerous lover The Joker (Jared Leto) will star in the spin-off or Batman (Ben Affleck), who is traditionally the superhero trying to stop the pair's criminal plans.

But Robbie has previously admitted she would love Quinn and The Joker to reunite.

She said: ''I'm trying to make that happen. Not for anything specifically, but just something - there's so much more to do.''

Meanwhile, Warner Bros is also working on a 'Suicide Squad' sequel and a spin-off for Will Smith's character Deadshot.