Swiss-based chocolate firm Barry Callebaut said Wednesday it was delaying its goal to sustainably source 100 percent of its cocoa and other ingredients by five years to 2030.

In 2016 the Zurich-based group adopted an ambitious plan to eradicate child labour in cocoa plantations and lift 500,000 farmers out of poverty by 2025, as well as aiming to use completely sustainable ingredients by this date.

The chocolate manufacturer, which supplies food industry giants including Hershey, Nestle and Unilever, said it would "use its sharpened targets as a springboard to extend the horizon beyond 2025."

The group now says it has added additional targets and that by 2030 it will have completely certified or verified cocoa and ingredients in all its products as sustainable, traceable back to the farms.

Oliver von Hagen, the group's director for sustainable global ingredients, said the company wanted to be "more specific about what we are committing to".

He said that the group will need the extra five years to ensure sustainable supplies for a remaining fifth of their ingredients.

The group said Wednesday that it had been working for the past six years to implement sustainable development standards for all its ingredients including dairy products, palm oil, coconuts and nuts.

Last year, around half of Barry Callebaut's products were made from sustainable ingredients, a spokesperson told AFP, up from around 23 percent in 2016.