F# constructor doesn't accept tuples?

I tried to use a tuple to create a new instance of a class defined in F#. To duplicate the problem, I tried the following code.

type test(x: int, y:int) =
    let distance =
        x * x + y * y |> float |> sqrt
    new (x: int, y:int, z:int) =
        new test(x, y)
let args = 1, 2
let test2 = new test(args)

It complains that

Error 1 The member or object constructor 'test' does not take 1 argument(s). An overload was found taking 2 arguments.

If I remove the non-default constructor, things are fine. I don't understand why it becomes two/three arguments instead of tuples.

Thank you very much.