The Federal Government has been called on to publicly explain its decision to award a multi-million-dollar contract to a company that has previously donated tens of thousands of dollars to the Liberal Party.

Key points: Vocus won the $2.8 million contract late last year through a limited tender

Vocus won the $2.8 million contract late last year through a limited tender It was for a scoping study on the planned Pacific high-speed internet cable

It was for a scoping study on the planned Pacific high-speed internet cable Vocus donated $44,000 to the Liberal Party in 2013 and $50,000 in 2016

Telecommunications company Vocus was last year awarded a $2.8 million contract to carry out a three-month scoping study on the planned undersea high-speed internet cable for Papua New Guinea and Solomon Islands.

Vocus donated $44,000 to the Liberal Party of Australia in 2013, and a further $50,000 in 2016.

Sorry, this audio has expired Calls for transparency over contract for Pacific undersea cable study.

The Department of Foreign Affairs and Trade (DFAT) awarded the scoping study contract through a limited tender, a process where only one or more potential suppliers are approached to apply.

Australia made an offer to help with the Pacific cable project last year after the Solomon Islands signed a deal with Chinese communications giant Huawei.

That deal unnerved security experts concerned about China's growing influence in the region, and the prospect of a Chinese company gaining access to Australia's internet infrastructure.

Marc Purcell, the chief executive of the Australian Council for International Development, told the ABC's Pacific Beat program the combination of the donations and the limited tender were "not a good look".

"The Government does have the ability under the Commonwealth Procurement Guidelines to have a limited tender," he said.

"While it has that power, the issue is the lack of transparency and what I think will raise eyebrows in Canberra is the fact that the preferred provider Vocus is a donor to the Coalition."

He said the nature of the limited tender meant there was only a small amount of information publicly available, and he has called on the Government to clarify the business case for the contract.

"It's not a good look. And I think because there is a high degree of public concern about accountability of the aid program, we're calling on the Government to make it more transparent," he said.

Sorry, this video has expired Senator Concetta Fierravanti-Wells discusses the undersea cables with Beverley O'Connor

A deal on how the project will be funded is expected to be announced in coming weeks, however the Government has already confirmed it will fund the majority of the project, and will do so out of its overseas aid program.

DFAT says company 'best placed' for contract

The internet cable project will be paid out of Australia's aid budget. ( Supplied: DFAT )

DFAT said Vocus was awarded the scoping study contract on account of its "extensive, recent experience with similar infrastructure projects", and that the company was "assessed as being best placed to explore potential cable solutions".

It said the tender process was carried out in accordance with the procurement rules and transparency requirements.

Vocus has recently installed submarine cable infrastructure between Darwin and Port Hedland. Another project linking Perth, Jakarta and Singapore is scheduled for completion in July.

A new cable system will improve internet connection speed across Solomon Islands. ( Supplied: Asian Development Bank )

The ABC understands Vocus did not have the capacity to complete submarine cable builds at the time the donations were made.

"This donation was made prior to the Vocus acquisition of Nextgen Networks, the entity within Vocus group responsible for this project," the company said in a statement.

The company said the political donations were made by its former board and management team.

Its management team has gone through major changes in recent months, with former CEO Geoff Horth stepping down in late February by "mutual agreement" after two years in the top job.

Shortly before his departure, Mr Horth told the ABC that Vocus was well-placed to deliver the scoping study on behalf of the Australian Government.

"I think what we can demonstrate is as an organisation, we're a listed Australian company that has a great reputation and strong credentials in designing and building these types of systems," he said.

The scoping study was completed and handed to the government at the end of March.

The project's next phase is expected to begin in the second half of this year, with the cable due to be completed by the end of 2019.