It sounds like you will be required to set up as a bare minimum a permanent establishment. In most cases we do recommend setting up an Australian company with the shares held by the overseas entity.

The Australian company will pay tax on the profits and the profits can be repatriated via dividends (generally without further Australian tax). The overseas entity/s can ensure a reasonable amount of the profits are directed back to the parent entity via reasonable profit margins on sale of the equipment to the Australian subsidiary and for provision of overseas expertise, management and staff. You will need to address transfer pricing issues.

Much depends on the way in which you intend to conduct business. If you set up a physical presence with your own employee/s and both market and maintain the equipment from that base in Australia, you will almost certainly have a 'permanent establishment'. That will trigger Australian tax on both the sale and the maintenance activities. Whether that presence is structured as a branch or a local subsidiary, transfer pricing issues need to be considered as may tax treaty provisions (depending on your country of residence). You will also need to think about expatriate tax issues for any employee's you send - individual tax rates hit 38.5% @ A$80,000 and 46.5% @ A$180,000 .

On the other hand, if you simply sell from home base and deliver to Australia for an independent operator to maintain, there might be little or no Australian income tax issues. In the middle ground there are various 'shades of grey'.

If you want some local credibility you should set up a local Australian Company EG X Pty Ltd. You need a local director. We look after a number of subsidiaries like this and also administer their payroll/salary packaging for the expats. We are in Perth, Western Australia where the bulk of the Mining Industry work is. Perhaps email me on charles@sondergaard.com.au and we can discuss further - skype?

If you want some local credibility you should set up a local Australian Company EG X Pty Ltd. You need a local director. We look after a number of subsidiaries like this and also administer their payroll/salary packaging for the expats. We are in Perth, Western Australia where the bulk of the Mining Industry work is. Perhaps email me on charles@sondergaard.com.au and we can discuss further - skype?

The taxation implications of setting up a permanent establishment in Australia and the staffing issues (particularly expats as highlighted by Fred) can result in significant fixed overheads

These would need to be assessed in more detail; in conjunction with the overall strategy plan, before any definitive advice could be provided

The use of a well-structured distribution / agency agreement is a common stepping stone

I Agree with David that it is most likely that it would be beneficial for an entity to be set up in Australia for these operations and if a company is best suited to your business as opposed to a trust the shares may be held by an overseas entity or individual.
Setting up as a trust with a corprate trustee should also be evaluated due to the 50% Capital Gain Tax Exemption avaialble in the event you sell the business. The general 50% capital gains tax is not available to companies. For this you would need a Australian Trustee -obtainable via an Australian Company (Corporate Trustee)
However depending on the number/value of sales and the number/type of staff/contractors employed it may not be essential to set up in Australia. If youa re able to use genuine contractors (as opposed to contractors that could be deemed to be employees) and sales are expected to be irregular I do not believe you would be required to set up an Australian entity. The commercial reality if you chose not to set up in Austrlaia would also be an important factor to consider as many Australians prefer an Australian Based entity to deal with in a day to day basis.

As always seek porfessional advice as soon as possible so all factors can be considered and the best structure advised upon