Newcomers Asia Pacific Telecom (APT) and Ambit Microsystems are teaming up to invest an estimated TWD2 billion ($65 million) in a combined 4G network in Taiwan.

The two companies, which are subsidiaries of electronics contract manufacturer Hon Hai (also know as Foxconn), have reportedly opened a tender for the network build, with interest from Alcatel-Lucent, Ericsson, Huawei and Nokia Networks, the Chinese-language Commercial Times said.

In late February the country’s telecoms regulator rejected a proposal to merge APT and Ambit because they failed to provide details on a strategic alliance with Taiwan Mobile.

The rejection came just a week after the National Communications Commission (NCC) said it was investigating complaints by three rivals of APT and Taiwan Mobile that the two operators’ 4G roaming agreement was illegal.

The NCC has since required that both operators build their own 4G networks. Ambit will need to have at least one operational 4G base station before its 4G concession expires in June, while each of the two companies is required to roll out 2,000 base stations this year, as detailed in their business plans, the Times said.

The regulator approved APT’s 4G licence in late October, giving it six months to offer 4G service. APT is the country’s fifth 4G player and said in October it planned to launch 4G service last year in the 700MHz band. But it has emerged that it is sharing Taiwan Mobile’s network and offering lower rates than Taiwan Mobile. This also has drawn complaints from the public and the attention of the regulator for possible fair trade violations.