He has raised the issue of tax cuts on and off for several months now as one of the ways on which to spend forecast surpluses, always with the caveat of them being targeted at low- to middle-income earners and being modest.
Mr Key said after his speech that no decision had yet been made on any such tax cuts.
But the fact that he included another mention in his conference speech suggests they will form part of National's campaign for the September 20 election.
A $212 million regional road and bridge-building programme was the centrepiece of his speech.
The party's campaign slogan "Working for New Zealand" was unveiled at the conference, as was #Team Key, a one-stop hub for social media related to National policies and candidates.
Campaign chairman Steven Joyce announced that the party had set numerical targets for the party vote in specific electorates, rather than a percentage, in a bid to lift voter turnout.
This time Mr Joyce and campaign director Jo de Joux have targeted not just seats where National polled high in the party vote last time but some Labour-held seats, including Christchurch East, Dunedin South, Mana, New Lynn (the seat of Labour leader David Cunliffe), Palmerston North, Port Hills, Rimutaka, Te Atatu, Wellington Central, West Coast-Tasman and Wigram.
Labour and the Opposition featured relatively strongly over the weekend, even though Governments don't usually give opposition parties any profile.
But Mr Key, Mr Joyce, Finance Minister Bill English and Attorney-General Chris Finlayson all took an opportunity to knock the Opposition.
Mr Finlayson raised the spectre of a multi-headed opposition Hydra that kept springing new heads.
Mr English said the Greens were vindictive and dangerous.
Mr Joyce posed a rhetorical question: "If Laila Harre, Hone Harawira, Pam Corkery, Kim Dotcom, Russel Norman, Metiria Turei, David Cunliffe, Matt McCarten, and John Minto are the answer, can we please have another look at the question?"
And Mr Key took aim yesterday in his speech.
"Labour has David Cunliffe, who takes himself so seriously that other people don't have to," Mr Key said.
"The Greens have two co-leaders who want to be co-deputy-prime ministers in some kind of bizarre job-sharing experiment.
"Internet Mana - the Maori radical meets file-sharing party - is a strange mix of goodness know what they stand for."
Mr Key denied that National's coalition potential partners following the election were just as complicated as the Labour Party's options.
"For a start off we are likely, if we form the next Government, to be very dominant in that Government, as we have been over the last six years and that puts a very different perspective on governing relations," he told Radio New Zealand this morning.
The Labour Party, which at the moment was polling under 30 per cent, needed other parties to govern, including the Green Party if they reached 11 or 12 per cent, Mr Key said.
The National Party had not yet made a decision on who future coalition partners would be, he said.
PM unveils $212m road project spend
National has hand-picked 14 regional roading and bridge projects for acceleration using proceeds from state-asset sales.
With just 82 days to go to the election, it is clearly a pitch to the regional vote. Most regions can claim some special treatment.
Prime Minister John Key announced the $212 million package at the National Party conference in Wellington. Five projects will definitely be accelerated at a cost of $80 million; six projects will be investigated for $5 million and $115 million will be budgeted for them, if they are approved; and $12 million will be used to investigate and design three large projects. If those three go ahead, the estimated $212 million needed to fund them would have to come from the national land transport fund.
Mr Key rejected a suggestion that it was a case of old-fashioned pork-barrel politics, saying the Government had spent money around New Zealand. "But it does recognise that across the regions, we need a stronger infrastructure."
He told the conference the regions had led New Zealand's economic recovery. Transport Minister Gerry Brownlee said the projects had been identified over a number of years by local governments as high priority.
Labour leader David Cunliffe said the package was no substitute for a strong economic development plan. National had cut back the $330 million a year for regional roads to $160 million a year so the measure was just putting back a little that they had taken away.
"It is frankly a little disappointing."
Greens co-leader Russel Norman called it an election bribe using the state-asset-sale "slush fund".
Mr Key reiterated on Radio New Zealand this morning his belief the roading projects were significant.
"The Kawarau Bridge is a one-lane bridge.
"Now it's stopping really, as a one-lane bridge from having a special housing area, it certainly has a big impact on tourism there and as anyone who knows who travels around there, there's quite a log-jam."
He denied the funding was an election bribe.
"The building of infrastructure has been a big plan for this Government...we believe that having a strong infrastructure basically builds economic growth and improves the quality of living for New Zealanders."