Australia's spy agencies were so concerned about the security and strategic risks posed by a plan for Chinese firm Huawei to build an internet cable linking the Solomon Islands to Sydney that the Turnbull government will now largely pay for the project itself.

The Department of Foreign Affairs has confirmed it has taken responsibility for the undersea fibreoptic cable, including paying for the bulk of the project – which will cost tens of millions of dollars – through the overseas aid program.

Australia will now spending millions of dollars installing the undersea internet cable to the Solomon Islands. Credit:James Brickwood

The cable will provide fast and reliable internet to the small Pacific island nation, which now relies on satellites.

The step is highly significant as it shows the lengths to which the Turnbull government was willing to go to ensure the cable project could go ahead without Huawei's involvement.