THE chief executive of HJ Heinz, one of the world's biggest food manufacturers, has again taken aim at Coles and Woolworths for flooding the market with private label goods, which has forced it to shut one factory and downsize two others as its margins are squeezed to breaking point.

William Johnson, executive chairman, CEO and president of the $US16.4 billion Pittsburgh-based Heinz, told investors the company has had to rework its strategy in Australia to cope with the growing domination of private label goods and the never-ending discounting on branded goods by the supermarket chains.

Outspoken ... William Johnson. Credit:AP

''The reality on Australia [is that it has] almost come to the point that it's … immaterial to us going forward because it has taken such a hit,'' Mr Johnson said. ''We are confronting a combination of weak categories, relentless promotional pressure and growing private label, as well as executional issues.''

It is the third time this year a senior Heinz manager has singled out Australia when updating US analysts on the quarterly performance of the global food supplier, with Heinz's chief financial officer, Arthur Winkleblack, in August blaming Coles and Woolworths for fostering an ''inhospitable environment'' for suppliers.