MELBOURNE - Australia on Thursday announced its intention to block two Chinese companies from bidding for a 99-year lease over a stake in Ausgrid, in yet another demonstration of its obscure and inconstant strategy towards Chinese investors.

It's high time for Australia to put all parties on the same page and implement its strategy in a unified and coordinated fashion, before its deeply confused investors lose interests.

Policymakers in Canberra, who still seem to hold onto cold-war mentality and viewing Chinese buyers via tainted glasses, pulled the plug Thursday on the 50.4 percent stake of Ausgrid lease bid at last minute.

Australian Treasurer Scott Morrison had voiced the preliminary government decision blocking the sale of the electricity network company to both Chinese bidders on security grounds.

New South Wales (NSW) state has been recycling state-owned assets to pay for much needed transport infrastructure and capital works.

If Australia keeps sending mixed signals to Chinese bidders, it would eventually cast the impression as an unpredictable investment environment to Chinese buyers as well as other potential investors.

We have seen Prime Minister Malcolm Turnbull and states governments' leaders paying visits to China, accompanied by strong trade delegations, with business on top of their agenda.

Australia's leadership clearly expressed their desire to enhance economic relations with China, more specifically, attracting investments.

Chinese investors responded the call with solid actions, as they came and participated in the biddings.

However, when it comes down to the real deal, the Australian government got cold feet. At times, Chinese investment got blocked over so-called national security concerns after lengthy negotiations, leaving a budget hole without a Plan B, as one the opposition leader said.

It was seen as a major setback for NSW government, who just lost the opportunity to raise funds for state infrastructure projects.

Moreover, the so-called security concern remains a mystery. Scott Morrison said he can not reveal the national security interests involved in the blocking of the sale.

"The only person who's security-cleared in this room to be able to hear the answer to that question is me," he said.

The same scenario has been witnessed in many Chinese investment cases, such as the partial lease of the Darwin Port, the sale of S Kidman and Co Limited, the country's largest private land owner, and the list goes on.

Concerns of potential consequences have been raised among Australian business elites.

Andrew Parker, partner and the Asia practice leader at PwC, said in a joint opinion piece with Bates Gill in Australian Financial Review that China as the world's second largest economy, is too important to ignore, and Australia should keep pace with a fast-changing China.

"We face new circumstances, new challenges and new demands. This requires a new way of thinking and a wider strategic conversation."

Parker, together with Bates Gill, professor of Asia-Pacific strategic studies a the Australian National University, both voiced that Australian economic interests should figure much more prominently in strategic deliberations over China.

Given the critical importance of Australia's economic relationship with China, throwing back Chinese bidders constantly setbacks would not serve Australia's long-term national interests.