Sharpe swings back into NSW parliament

In politics, they say, what goes around comes around.

And so it was in the NSW upper house on Wednesday, when the vacancy created by Labor's Penny Sharpe was filled by none other than Labor's Penny Sharpe.

"Just pretend it didn't happen," Greens MLC David Shoebridge yelled at a joint sitting of parliament as members prepared to vote on who should take the empty place.

Ms Sharpe had previously told the Star Observer she would not seek to re-enter the upper house if her bid to win the newly created seat of Newtown was unsuccessful.

But she had a change of heart after the seat was claimed convincingly by Greens contender Jenny Leong.

Ms Sharpe thanked "those who encouraged me back" and said she was looking forward to "fighting some Tories" with party colleague Daniel Mookhey, who was elected to fill a second casual upper house vacancy.

The parliament also endorsed Jennifer McAllister to fill the NSW Senate vacancy created by John Faulkner's resignation.