Over the same period, Labour leader Andrew Little was wrestling with the public breakout of internal discontent over his decision to shoulder-tap Willie Jackson as a Labour Party candidate at the time. That broke an otherwise strong start to the year for him.
English told One News it was a good start but all elections were close.
Little told the Herald National's drop showed English was not getting a honeymoon - and that people wanted a change.
"Unusual for a party in Government with a new leader that there should be a four point decline. That's normally when you'd get the benefit of change - a bit of a honeymoon.
That doesn't seem to have happened."
Asked about his own seven per cent result compared to English's 31 per cent, he said "ho hum. Incumbents will always rate well - that's just life."
He was pleased with the poll given Labour had moved up and National had dropped. "The numbers are heading in the right direction from my point of view. We still have seven months to go and we are out there selling my plan for New Zealand."
NZ First will be the kingmaker on the poll results - there just five points between the National and Labour-Greens blocs, but neither could form a Government with their preferred support partners: Act, the Maori Party and United Future for National and the Green Party for Labour.
NZ First had pulled up one point to 11 per cent - even with the Green Party. Act, the Maori Party and Mana Party were all on one per cent.
The speed of Key's drop in the preferred Prime Minister rankings contrasts with that of former Labour leader Helen Clark who continued to poll fairly highly for months after resigning.
The poll of 1000 voters has a margin of error of +/-3.1 per cent.