Amcor announced on Thursday that well-regarded chief executive Ken MacKenzie will retire at the end of June, after 10 years at the helm, and hand the baton to Mr Delia, Amcor's chief financial officer.

The announcement took the market by surprise and Amcor shares, which have risen 23 per cent in the last 12 months, fell almost 5 per cent before closing down 54¢ at $12.34.

Mr Delia reassured investors and customers that the company was in good shape, that Amcor's fundamental strategy would not change and he was in "lockstep" with Mr MacKenzie over its priorities and future direction.

"I have been involved in the development of the company for the last nine years and the foundations of the Amcor way and the share value creation model will continue - these are key parts of our DNA," Mr Delia said.

"As CFO, I know our focus on shareholder returns and capital discipline which has been a key driver of returns - that will not change," he said.

"But there are opportunities to improve and we'll continue to evolve - we have been evolving for quite some time," he said. "We have been on a journey and each block in that journey builds on the next and that will continue."

Mr Delia said Amcor was committed to becoming a world leader in packaging innovation and needed to build its existing innovation capabilities.

He also flagged further organic growth and acquisitions in emerging markets such as China, India, south-east Asia, Latin America and parts of Europe, which currently account for about 20 per cent of Amcor's sales.

"That's an area that's been a real source of success for us, (but) we can certainly do more," he said.

"We've had a steady stream of acquisitions in the last three or four years and we expect that to continue. Relative to some of our customers we are relatively underweight in emerging markets and there's going to be more opportunities in emerging markets going forward."

Mr Delia ruled out further non-core asset sales, saying Amcor's portfolio was in good shape, and would not comment on the likelihood of further capital management.

There has been speculation that Amcor may return surplus capital to shareholders after missing out on buying major rival Constantia, which was acquired by French investment company Wendel in December in a deal that valued the company at $US2.8 billion.

Mr MacKenzie rejected suggestions that his decision to retire and the failed Constantia deal were linked.

"We knew the business well and had done work on synergies but it was not possible to get anywhere near an acceptable return for our shareholders," he said. "There is no disappointment there - I'm retiring but the two are not linked."

Under Mr MacKenzie's control, Amcor has been transformed into one of the world's largest packaging companies, with operations in 43 countries, revenues of $11 billion, earnings before interest and tax of $1.18 billion and net profits of $737 million in 2014.

During Mr MacKenzie's time at the helm, Amcor's return on capital almost doubled from 10 per cent to 19 per cent and he engineered more than 20 acquisitions including the transformational $2 billion purchase of Alcan's packaging assets in 2009, Ball Plastics in 2010 and Aperio Group in 2012.

Mr MacKenzie took the helm of Amcor in 2005, shortly after a cardboard box price-fixing scandal claimed the scalp of former chief Russell Jones.

He closed plants in high-cost countries, sold commodity-style assets in favour of specialty and custom-designed products, improved the company's capital discipline and customer service and demerged the slower growing Australian fibre packaging operations in 2013.

However, Mr MacKenzie listed his biggest achievements as the implementation of a global operating model known as the Amcor Way and the quality and depth of talent of Amcor's staff.

"At the end of the day, changing culture is the hardest thing to do in business - we have a very strong culture of outperformance, it's a mindset that we strive to be better," he said.

He also flagged more acquisitions before he steps down.

"I'm still looking forward, I'm not looking back yet - the job's not done.

"My first priority is to ensure a smooth transition to Ron and I want to finish fiscal year 2015 well. Beyond that, I have no plans other than spending quality time with my family," he said.

Amcor is believed to be in talks to buy a controlling stake in a flexible packaging business in India.

Deutsche Bank analyst Mark Wilson described Mr MacKenzie's departure as a "minor negative", given the high regard in which he was held, but did not expect major changes to strategy or the company's focus on shareholder value creation.

Mr Delia, 43, was born in New Jersey in the US and is married with two young children. He has an MBA from Harvard and started his career in the packaging industry as a sales rep for American National Can Co.

He joined Amcor in 2005 and was one of Mr MacKenzie's first external hires, working as executive vice-president of corporate operations from 2005 to 2008. He then ran Amcor's rigid plastics business in Latin America from 2008 to 2011 before taking the role of chief financial officer in 2011.

Under his employment contract, Mr Delia will receive a fixed remuneration of $US1.7 million, comprising a base salary of $US1.4m and other benefits worth $US300,000. If all performance hurdles for short term and long term incentives are met or exceeded Mr Delia stands to receive total remuneration around $5.6m. Mr MacKenzie received $8.4m in 2014.

Amcor chairman Graeme Liebelt said succession planning had been underway for some time and Mr Delia was selected from a strong field of well-qualified candidates from Amcor's global management team.

"Mr MacKenzie felt it was the right time to pass the baton to the next CEO and the board thanks Mr Mackenzie for his extraordinary contribution to the company over the past 10 years," he said.