Keeping its Australian factories open has cost Ford more than half a billion dollars over the past seven years, the company’s global chief Alan Mulally said.

In an interview with News Corp in Sydney, he said that some 300 meetings had been held in that time in a bid to keep the plants active.

Mulally said the sharp decline in Falcon sales and reduced output at Ford’s car assembly line in Broadmeadows and the engine factory in Geelong were discussed weekly at the highest levels of the company in Detroit “ever since I started at Ford”.

He was in Australia to confirm plans to reintroduce the Mustang and unveil 11 other models that will replace the locally made Falcon and Territory from 2016. Mulally, who joined the carmaker from Boeing in 2006, said the decision in May to shut the Australian factories was made in Detroit about 48 hours before Ford employees on the production lines were told.

He said: “We really had been trying hard ... to make it work for years. Ever since I started we’ve been reviewing all the operations around the world and (Australia) was a regular part of our review process.

“I will always feel really good that we worked so hard (to keep Ford’s manufacturing operations in Australia). We take these decisions very seriously. It impacts a lot of people’s lives. It was a very thoughtful decision, a very hard decision.”

Despite company founder Henry Ford’s original vision to “manufacture cars where we had major markets”, Mulally said that exchange rates and cost structures made it more viable to best serve Australian customers from overseas factories.

Many Fords sold in Australia now come from Thailand, with which the country has a free trade agreement.

Ford’s chief operating officer Mark Fields said the three year notice was among the longest warnings of a factory closure. “The approach we took was to treat people respectfully ... and give them enough time to transition to the next chapter of their lives.”

Ford has manufactured vehicles in Australia since 1925 but it will become an import only brand by the end of 2016.