Rio, which is subject to a 64 billion US dollar takeover bid from the world's biggest mining company BHP Billiton, announced a review of near-term spending on growth projects in October.
Chairman Paul Skinner said the company would take a "little bit of time" over the review and may not release its decision until announcing its full-year results on February 17.
"We probably wouldn't necessarily publish anything definitive until early in the new year, and it may even be that we elect to combine this with the presentation of our annual results," he told reporters.
The delay means BHP Billiton's hostile bid for London-listed Rio could be under way by the time the company releases its decision.
The BHP bid, which has been given the green light by Australia's corporate watchdog, is currently being investigated by European Union competition regulators who are expected to make a decision by February 5 at the latest.
Skinner, who was at an Australian British Chamber of Commerce lunch in Melbourne, said he had no plans to meet BHP during his visit to Australia, adding that he still thought their offer undervalued his company.
He said he believed Rio shareholders backed the decision to reject the bid.
"There will inevitably be some differences of view but the centre of gravity of shareholder opinion is entirely supportive of the stance we have taken," he said.
Earlier this month Rio slashed iron ore output at its western Australian mines by 10 percent to bring production in line with revised customer requirements following a drop in demand from China.
Skinner said the review would be across operations but would not risk long-term growth.
"We are not going to do anything that compromises the ability of the organisation to grow, and hence, because iron ore is such an important component, we will pay particular attention to that aspect," he said.
Source: AAP NewsWire