Peters said the only relevant poll was election day, which would "show whether there is going to be a serious change or same old, same old".
He has previously been Deputy Prime Minister under the National-led Government between 1996 and 1998.
A One News Colmar Brunton poll released yesterday showed that NZ First had fallen two points to 8 per cent. But it remained in the kingmaker position, and could potentially form a government with Labour, which polled 43 per cent.
Meanwhile, Peters has taken aim at both Labour and National over their policies on charging for water.
But he will not go as far as saying he will veto Labour's water royalty in any coalition talks, saying he is still not clear about the details.
Speaking in Hastings, Peters said both parties' positions on freshwater would lead to unknown costs, and voters deserved to know what they would be paying ahead of the election.
"We need to have an honest answer from both parties as to what their taxes mean.
"Because no matter what you apply, Labour's or National's, it means a stiff charge for everybody who needs water in this country now."
Labour says it will introduce a royalty on commercial water use in rural areas, while National will not rule out a levy for the extraction of bottled, exported water says it is not interested in a broader charge.
Peters said he supported Labour's proposal to put price on bottled water - which matched his party's position.
But Labour's plans to apply the royalty broadly, including on fruit and vegetable growers, should cause "serious stress and alarm" in a food-producing region like the Hawkes Bay, he said.
"It will have a major implication for you in the Hawkes Bay and around regional New Zealand. Be very, very concerned here in the Hawkes Bay about this tax."
The policy was light on detail, he said, with no specified rate per litre. He said there had been estimates of $50m to $500m in possible revenue.
Labour has suggested it would charge 1c to 2c per 1000 litres but says it will set the rate after consultation. It also says it expects to collect $100m a year from the royalty.
The National Party's policy on water was "just as bad", Peters said, but for different reasons.
He said he expected New Zealanders to face new costs because of National's deal with the Maori Party to give iwi a greater say in the consenting process, including on water allocation.
"What the National Party has done is to pass laws where the division and the ownership and the charging for water will be 50/50 between the local body and Maori authorities," Peters said.
"When that happens ... you'll get a water charge coming through your mail. They will be coming and they will be charging and they will never have consulted you on it."
Speaking to reporters afterward, Peters would not say whether Labour's royalty on water would be a deal-breaker in any potential coalition talks after the election.
A 1News Colmar Brunton poll released yesterday showed Labour had overtaken National and could form a government with NZ First. NZ First fell 2 points in the poll to 8 per cent - a result which Peters refused to discuss: "You know what I think of your polls."
