The GMB Union has unanimously rejected a 2.5% pay offer from contractor Idverde.
A spokesperson for the company says they’ve made their financial position “clear” and are “disappointed” by the action.
The parks remain open and the International Masoor Cricket Tournament in Merton is still going ahead.
An Idverde spokesperson says:
“We are disappointed by the action taken by our colleagues at sites across Sutton and Merton. We continue with open, cordial and constructive discussions with colleagues and are still hopeful of a workable resolution.
“We are and remain open to solutions; we have made our financial position clear to union colleagues. Now we are looking to them for support and ways to find workable options that will help bring us closer together.”