National Party Leader John Key says Helen Clark is now more reliant on the Greens than ever before.

"The resignation of Gordon Copeland further undermines the façade of stable Government that Helen Clark has tried to project. Any significant policies will require even more horse trading among the smaller parties and Labour will find it even more difficult to implement any coherent agenda at all.

"The public will want to know what further concessions Helen Clark is prepared to make to the Green Party, United Future and New Zealand First in order to keep her make-shift coalition alive?"