The Democratic Alliance may take legal action over a multibillion-rand government tender for the supply of as many as 5m set-top boxes for digital terrestrial television.

“The DA is concerned that in a rushed attempt to partially meet the digital migration deadline of 17 June 2015 by delivering some set-top boxes this year, proper processes and evaluation may be circumvented and sidelined, rendering the tender process unlawful,” MP Marian Shinn said in a statement on Tuesday.

According to Shinn, the tender deadline closes today (Tuesday). It was published in November by the Universal Service & Access Agency of South Africa (Usaasa), she said.

Government has said it will subsidise the set-top boxes for as many as 5m poorer households as part of South Africa’s long-delayed migration from analogue to digital television.

Usaasa spokesman Khulekani Ntshangase has hit back at Shinn over her remarks, saying the agency is following a legitimate legal process.

“We have issued tenders and we are working with the national treasury on this process,” Ntshangase said. “All of our processes are above board. We are not worried about the DA.”

He added that the DA should be “supporting us” and not “trying to derail this process”.

“Our position will prevail in court. We haven’t done anything wrong,” he said. “People can say whatever they want. We will continue to do our work.”

Shinn said the DA was questioning the validity of the process for a number of reasons.

Firstly, she said, the broadcasting digital migration policy has not been approved by cabinet.

Secondly, the set-top box tender document calls for two prices: for boxes with set-top box control and for those without.

In addition, the direct-to-home technology standards have not been approved.

The “low-key manner” in which the tender process was conducted has also raised concerns for the DA. Shinn said it “sidelined many companies that would have submitted bids, casting doubt over whether the process will be fairly adjudicated”.

“Most of the 145 companies that attended the bidders’ briefing meeting on 2 December 2014 were invited. Bidders were briefed on supply of set-top boxes, before fundamental aspects of their functioning had been decided and finalised.”