Having put their collective feet up on the desk as they scratch their navels and contemplate retirement, baby boomers have been overtaken by Gen Xers as the workforce's most productive generation.

A survey of 170 Kiwi and Australian HR managers found Generation X employees - typically aged between about 30 to 48 - were the hardest working, easily out-polling baby boomers and Gen Yers, with the under-30 demographic polling just 3 per cent of the vote.

"They're just getting a little older," surveyor Directioneering International's managing director Nick Plummer said of the declining output of baby boomers.

"The next generation coming through are picking up the reins. I don't think it's that baby boomers didn't work hard enough, they were a very hard working group and a very loyal group. They are just getting older, and have been overhauled by this younger, more energetic group."

While recognised as the most loyal workers (79 per cent), baby boomers were found to lack ambition and be the least comfortable with change.

Gen Y workers were the most likely to want clear career progression (59 per cent), ongoing training (57 per cent) and were the most mercenary (51 per cent). They were also seen as the most open to change (43 per cent) and the most likely to want to be challenged (37 per cent).

The results reflected a changing workforce that would create challenges for employers over the next decade, Mr Plummer said.

"As you move through those generations you find a greater desire for short-term reward and a more mercenary attitude. There's heavier cynicism about employers. There's a change of attitude and that is what employers have got to contend with."

The influence of technology and ability of people to work for themselves more meant management techniques would have to change.

Managers would have to find a way to inspire and reward rather than simply instruct.

EPMU acting national secretary Ged O'Connell wasn't surprised by the way HR professionals viewed the workforce. The idea that employees provided maximum value for five to eight years before slacking off had been popular with managers since the 1990s.

"That may be true from the hotshot manager's perspective," Mr O'Connell said. "You get comfortable." But that view didn't reflect the true value of ageing employees, particularly in blue-collar roles, he said.

"Yes, their waistline gets bigger and they hardly fit in their overalls any more but the fact is they have been around for 10 or 15 years and are hugely knowledgeable."

Generation game

Baby boomer
Born during the post-World War II population boom of 1946 and 1964. Now aged between 48 and 66. Loyal workers, but lack ambition and are uncomfortable with change.

Gen X
Born post-baby boom, roughly between 1965 and 1983. Now aged 30-48. Hard working. Ambitious.

Gen Y
Follows Gen X. Starts about 1983 and ends about 2004. Now aged 9-30. Least hard working. Most ambitious.