Australia treasurer would block a Glencore-Rio Tinto merger

* Tax revenue loss could be hurdle to any deal

* Glencore (Xetra: A1JAGV - news) free to refresh bid for Rio Tinto (Xetra: 855018 - news) under UK rules

* Commodity price slump weighs on Glencore firepower in any bid (Recasts; adds comment from source, treasurer's office)

MELBOURNE, April 8 (Reuters) - Australia's treasurer has told business representatives he would not allow Glencore Plc to merge with Rio Tinto due to concerns about losing tax revenue, a person familiar with his comments said on Wednesday.

Treasurer Joe Hockey said based on the tax implications he had seen from the treasury, he would not allow a Glencore takeover of Rio, Australia's second biggest miner and one of its biggest taxpayers, the person said. He declined to be identified due to the sensitivity of the issue.

Treasurer Joe Hockey's office declined to confirm the comments.

Four people said Hockey had spoken at a private meeting on March 30 organised by the Business Council of Australia and including members of the Minerals Council of Australia, but three would not give details.

Glencore approached Rio Tinto about a merger last July that would have created a $160 billion mining and commodities trading giant. Rio revealed in October it had rebuffed the approach, but under UK takeover rules, Glencore is now free to make a new bid, following a six-month breather.

"Any takeover would have to go through the normal processes at FIRB (Foreign Investment Review Board)," a spokesman for Hockey said.

Australia's treasurer has the final say on any takeovers by foreign companies, based on recommendations from FIRB.

Hockey's comments were first reported by the Australian Financial Review on Wednesday. Citing multiple sources, it reported the treasurer said there was "no way" he would allow a Glencore takeover of Rio Tinto "on my watch".

Hockey stunned investors in late 2013 when he blocked a A$2.8 billion takeover bid for Australia's largest agribusiness, GrainCorp by Archer Daniels Midland Co, saying it was against the national interest.

Rio Tinto Chief Executive Sam Walsh earlier this year said Rio would never be taken over by Glencore because there was no value in it for shareholders and regulators, including "people who collect tax", would never let it happen.

The main attraction for Glencore in Rio Tinto is its high quality, low cost iron ore resources. Iron ore prices have plunged in the six months since the world No.2 iron ore miner revealed it knocked back Glencore, weighing on the Anglo-Australian giant's shares.

But Glencore's shares have fallen even more than Rio's over that time, possibly putting Rio out of its reach for the moment.

Rio, Glencore, the Business Council of Australia and the Minerals Council of Australia declined to comment on Hockey's remarks.

(Reporting by Sonali Paul; Editing by Joseph Radford)