Speaking on BBC Radio Four's Today programme on Thursday, Mr Watson said MP Chris Williamson, who was suspended on Wednesday over his "pattern of behaviour" over the antisemitism crisis, had been "deliberately inflammatory".
He said: "I’ve been very, very concerned that his comments have almost been deliberately inflammatory and causing offence to not just parliamentary colleagues but people in the Jewish community who understandably have a real concern about antisemitism in the Labour Party."
When asked whether Jeremy Corbyn should be prime minister, Mr Watson replied he "could very easily" be prime minister.
Mr Watson later appeared on BBC Five Live and told host Emma Barnett the inquiry into Mr Williamson had to be "very quick".
He said: “I'm not going to set a date but I do know our General Secretary is under a lot of pressure on this. And she has recently - you'll have seen her public announcements - we have recently significantly increased the number of staff we have to look at these disciplinaries.
“I would imagine, in order to gather evidence and for him to have his case heard, it's probably a matter of weeks, but you must ask the General Secretary who deals with this stuff. But it's definitely weeks not months, in my view."
