Earlier, English said he was focused on his Members of Parliament and working to continue the good work the National Government has delivered under Key.
Speaking on Newstalk ZB's Mike Hosking Breakfast show this morning, the country's new leader acknowledged Key's solid work and what the country has achieved under his leadership.
But changes are ahead, he said.
"I'll have to appoint a Cabinet - and there'll be some changes. A certain amount of change has to happen.
"There's been a lot of internal discussion about the degree of that and we'll be continuing that discussion over the next week or so.''
English was coy on whether he may be tempted to go for an early general election, acknowledging he was not officially Prime Minister yet - and therefore not in a position to make that call.
"Technically, I'm just the sole candidate for the election to the leader of the National Party on Monday. Once that happens, then we'll be in the position to think about those things.''
The idea had been "bandied around'' though, he said.
"But this is a Government that has been characterised by stability and predictability - and you shouldn't expect sudden U-turns.''
English would not be drawn on who he preferred to be his deputy - Ministers Simon Bridges and Paula Bennett are vying for for the role.
"I've kept at arm's-length from that [discussion],'' he said.
"I've worked with both of them, probably more closely with Paula, in recent years. But the caucus is having a continuing - a very constructive and I have to say a pretty testing discussion - as they did with me for the first few days, with both of those people.
"The caucus knows we've got to reset a bit from the dominance John had. It's gonna need more people with a wider range of abilities and that's what they're working through right now."
He was confident in his ability to communicate with the New Zealand public and particularly about what voters wanted.
There was also a continued promise for a strong economy, safe communities, jobs, better incomes and supporting families.
His time as leader would ultimately be judged by the cohesive work of Government and the ongoing results for New Zealand, he said.
Meanwhile, family members connected to the Pike River tragedy have requested a meeting with English to discuss a potential new plan to re-enter the mine's drift.
Spokesman for the families, Bernie Monk, said now was the chance to make good on Key's promise at the time.
Monk, who lost his 23-year-old son Michael in the tragedy, said: "We were told everything would be done to get our boys out. But now, when experts are telling us re-entry can be done safely, the Government wants to permanently seal the mine.
"As the new leader of the country, Bill English has the opportunity to do the right thing and work with us to get our boys, and any evidence of what happened, out of that hole.''
The family members will be at Parliament next Tuesday , where they hope to get an audience with the new Prime Minister.
