Winston Peters is tough when it comes to government negotiations, according to former New Zealand Prime Minister Jim Bolger.
Mr Bolger negotiated a coalition with Mr Peters, when the MMP was introduced in 1996.
Behind closed doors Mr Peters is "tough" to negotiate with, "but he has his positions", Mr Bolger told Q+A.
Respect, being able to find a common accord, and putting issues aside where there's no possibility of agreement, was Mr Bolger's advice when it came to negotiating with other parties after an election.
Mr Peters will start negotiations to form the next Government, once the election results are finalised on October 7.
"The whole concept of MMP, is to have a multi-party Government that requires compromise and listening to the other side and that both sides must accept some policies they campaigned on are likely not to be implemented," Mr Bolger said.
"You have to look at how you will make progress forward; you have to move beyond the campaign, you're looking forward to a solution."
When it came to the MMP system, Mr Bolger believed the Greens were failing to understand the concept by not speaking to both parties.
"My perspective, the Greens want to influence the country on an environmental approach on a range of issues ... then why not speak to both sides, I think they fail to understand MMP if they do that," Mr Bolger said.
"The Green party has an opportunity to become an influential voice for the causes they hold dear."