The pair are the last remaining of the party's original seven MPs who entered Parliament in 1999, and will be remembered as such when they step down at this year's election.
Both will deliver their speeches this week, with Ms Kedgley to kick off the valedictory season tomorrow as the first of 14 departing MPs to bid final farewells.
Changes to the Green Party line up have frequently raised questions about the party's survival, first with the death of co-leader Rod Donald in 2005 then with the resignation of co-leader Jeanette Fitzsimons in 2009.
"People have stopped predicting our demise, because when Rod died they said well that's end of the Greens, and then they said that when Jeanette left,'' Ms Kedgley said.
"It's just a normal process of renewal, and we're just handing the torch to the next generation, and I think that's incredibly healthy and the way it should be.''
Mr Locke said the drama that went with the party's arrival in Parliament was probably one of the reasons people had focused on the original group.
"It was a sort of very refreshing thing to a lot of people who liked Green politics, and shocking for the people who didn't - you could see that in the way the National Government went to quite extreme lengths to try to stop the Greens coming in.''
However, there appears to have been a changing of tides over the last decade, and both Mr Locke and Ms Kedgley acknowledged greater public acceptance of Green policies.
In Parliament too, the shift in attitudes has been notable - once labelled "extremists'', Green MPs are now considered more mainstream, and the bashing they once suffered from across the parliamentary benches has somewhat faded.
Although neither would be a stranger to the party when they left Parliament, both made it clear they were not intending to be backseat drivers.
"That is the challenge for any MP that has played some sort of a leadership role in an area in the past, you don't want to be in the background saying you're doing things wrong, and undermining their authority,'' Mr Locke said.
