Tensions in Victoria's Labor government over the assisted dying bill have spilled out in an accidental text message.

Health Minister Jill Hennessy called Deputy Premier James Merlino a "c---" in a text message sent to him by mistake on Wednesday night, it has been confirmed by numerous parliamentary sources.

Mr Merlino, a fierce opponent to the government's bid to legalise a strictly monitored euthanasia scheme, had proposed an amendment which would have killed off the bill, long championed as a flagship policy by Labor.

Victoria's health minister Jill Hennessy reportedly sent an expletive text message to the Deputy Premier. (AAP)

The amendment was narrowly defeated and it's understood Mr Merlino is angry about the text message from his colleague.

His office declined to comment on the matter.

A spokeswoman for Ms Hennessy wasn't giving anything away.

"The minister doesn't comment on private conversations," she said.

News of this text message emerged as the marathon debate into assisted dying continues at state parliament.

After an all-night session in parliament spent discussing several amendments, MPs adjourned for a short time before debate resumed at 6am.

Victorian Premier Daniel Andrews (centre) addresses parliament addresses parliament as the Voluntary Assisted Dying Bill 2017 is debated in the lower house.

Members take their seats to vote on an amendment to the Voluntary Assisted Dying Bill 2017 as it is debated in the lower house at the Victorian Parliament.

The proposed laws state that terminally ill people with less than 12 months to live and who are suffering unbearable pain would be able to request lethal medication.

There are hundreds of disputed amendments to the bill, which has been backed by Premier Daniel Andrews.

Tensions within Victoria's Labor government over the assisted dying bill have been running hot.