The Australian Competition Tribunal has upheld a decision to block a network sharing agreement between wireless internet firms Telstra Group and TPG Telecom, TPG said on Wednesday.

The Australian Competition and Consumer Commission (ACCC) had ruled against the plan in December, saying it would bring "a real risk that TPG and Optus will invest less in critical infrastructure".

Optus, the country's No. 2 wireless internet provider and which is owned by Singapore Telecommunications, had opposed the deal, saying it would build Telstra's market dominance.

(Reporting by Harish Sridharan in Bengaluru; Editing by Subhranshu Sahu)