The Office of the Revenue Commissioners has brought a High Court challenge to a decision that millionaire developer Robert "Pino" Harris is entitled to some €9 million in income tax refunds arising from expenditure on the luxury yacht, the Christina O, which was bought for €65 million in 2000.

The case opened before Ms Justice Mary Laffoy yesterday and arises after Mr Harris claimed certain income tax reliefs arising from his status as a member of a limited partnership registered under the law of the Cook Islands, the Christina O Limited Partnership.

Mr Harris claimed the tax relief for expenditure related to the purchase in 2000 by a venture partnership of the luxury yacht, the Christina O, which had previously been owned by Greek shipping magnate Aristotle Onassis.

Mr Harris claimed the partnership was established for the purpose of acquiring and operating high-class luxury yachts and that, in the course of its business, the partnership acquired and refurbished the Christina O for approximately €65 million.

In his tax return for the year to April 5th, 2001, filed in January 2002, Mr Harris claimed relief for trading losses, capital allowances and interest arising from the purchase and refurbishment of the Christina O by the partnership.

In October 2004, the Appeal Commissioners decided that Mr Harris was entitled to set off against his entire income, capital allowances and interest payments arising from the partnership. The commissioners determined that Mr Harris was entitled to a payout of €9.12 million.

The Revenue challenged the Appeal Commissioners' decision. Opening the full appeal yesterday, Eoghan Fitzsimons SC, for the Revenue, said his clients were "dissatisfied" with the Appeal Commissioners' determination. The Revenue had "no problem" that Mr Harris, an Irish resident and taxpayer, could offset losses against the partnership, which is registered in the Cook Islands. However, it had a problem with his being able to offset the losses against his income.

When Mr Harris became involved with the venture, he had invested €144,000 and provided €14.3 million as a loan, giving him a share of just over 4 per cent of Christina O Limited Partnership, counsel said.

The case continues today.