She told the Herald Walker made "a personal decision that is not reflective of the performance of WellingtonNZ".
"We always welcome discussions about the best way to operate, and if our shareholders decide a review is in order we will gladly contribute."
"He has done a great job uniting the team and building a greater sense of purpose. We're sad to see him go, but we're confident he has created a great foundation for the next phase of WellingtonNZ's important work helping to make the Wellington region wildly famous."
In mid 2017 former chief executive Chris Whelan hung up the boots after less than two years in the role.
His time at the helm ended up being tainted by criticism over his spending on nights out.
He put expensive dinners and fine wine at high-end restaurants on his Wreda credit card with claims it helped to land new business.
Then mayor Justin Lester said it didn't reach the threshold for legitimate expenses.
Walker has agreed to stay on until the end of June 2020 to ensure a smooth leadership transition and help the Board secure the "right" replacement.
"While we're sad to see Lance leave, we understand his desire to look at new opportunities and wish him in well in those endeavours", Bridges said.
WellingtonNZ issued a press statement late this afternoon publicly announcing the news.
The board had regretfully accepted Walker's resignation, Bridges said.
"Mr Walker had made a significant difference to the focus, culture and performance of WellingtonNZ, uniting the organisation in its mission to make the Wellington region wildly famous.
New Porirua mayor Anita Baker said it was time for a review of WellingtonNZ.
The turnover raised questions about what was going on within the walls of the organisation, she said.
"It's never good to have them turning over like that. Why are they leaving?"
Porirua was struggling to see the benefit of its contribution which amounted to about half a million dollars annually, she said.
Baker said there was no indication a change in leadership was imminent when she met with WellingtonNZ representatives just before Christmas.
Wellington City Council Associate Economic Development portfolio leader Nicola Young said the council gave $12.6m to the organisation annually.
She wanted the city council to review its investment in WellingtonNZ.
"We need to think long and hard about its role and whether it's working."
Losing a chief executive every two years was expensive and unsettling, she said.