Apple has raised its estimated capital expenditure plan by the value of $280 million this year.

Notes filed with the US Securities and Exchange Commission confirm the company will be investing in a new second campus in Cupertino, its new data centre in Newark and this year's round of investment in its retail stores.

Apple is also spending $225 million on replacing existing assets and infrastructure. Total expenditure will reach $700 million this year, up from Apple's previous $420 million estimate.