What's happened to the "high quality advisory group" that John Key and Rodney Hide promised they would task with the challenge of investigating how New Zealand would close the income gap with Australia by 2025?

Nearly nine months into this Government's (first?) three-year term, nothing has emerged. Yet before becoming Prime Minister, Key made huge political capital out of the fact that New Zealand's income on a GDP per capita basis had slid markedly during his predecessor's near nine years in power.

Within a week of National securing the most seats at the 2008 election, he had signed a confidence and support deal with Hide which spelled out their parties' joint aspirations for greater prosperity for New Zealanders - with Australia singled out as the benchmark.

Attaining the "concrete goal" of closing the income gap by 2025 would require a sustained lift in New Zealand's productivity growth to 3 per cent a year or more.

The political leaders' ambition was crystal clear: a high-quality advisory group would be established to investigate the reasons for the decline in New Zealand's productivity performance, identify superior institutions and policies in Australia and other more successful countries, and make credible recommendations on the steps needed to fulfil National and Act's aspirations.

About 10 days ago, the Wellington rumour mill was running hot that a paper would be discussed at the next Cabinet meeting. But nothing eventuated.

Hide's people now say the chair of the advisory group may be announced next week when the Act leader gets back from holiday. A couple of names have been under consideration.

Political sources suggest they are former National leader and Reserve Bank Governor Don Brash and former Treasury secretary Graham Scott.

The political drum goes that Hide had all but secured support for Brash to chair the group - right down to suggesting who else should be among the membership. But Bill English - who has employed Scott as his "purchase adviser" - preferred his former Treasury boss (the Finance Minister was a Treasury analyst before entering politics) over his former party leader.

Those of an unkind bent are saying that English - whom Brash toppled for National's leadership - does not want him running the ruler over New Zealand's economic performance against its largest neighbour.

Frankly, both English and Brash are better than that.