NSW MPs sing goodbye to Greg Smith

In a rare and somewhat unconventional show of bipartisanship, NSW parliament has broken into song to farewell former attorney-general Greg Smith.

Mr Smith, who will return to the legal profession after a career in politics, delivered his valedictory speech to parliament on Tuesday. He will retire at the March state election.

Mr Smith ended his speech by inviting MPs to join him in singing the World War II-era song We'll Meet Again.

The respected lawyer's decision not to recontest his northern Sydney seat of Epping did not come as a surprise - he was dumped from the frontbench in April by new premier Mike Baird.

As attorney-general, Mr Smith faced criticism from political opponents and sections of the media for being soft on crime, even being dubbed "Marshmallow Man".

However, after being initially critical of the government's mandatory sentencing plans this year, he decided to support tough measures to combat alcohol-related violence.

The about-face came to define his stint as attorney-general.

In his farewell speech on Tuesday, Mr Smith defended his record.

"Clearly, my views, whilst well received by many and supported by evidence, were anathema to those who wanted to continue the tough law-and-order line," he told the chamber.

"My opponents largely ignored the reforms I made to toughen laws against violent behaviour."

Mr Smith has been in parliament since 2007.