Sir Tony O'Reilly, Ireland's first billionaire tycoon and former owner of the Independent newspaper titles, has been labelled insolvent and left pleading with a Dublin court for more time to sell off assets – including his 750-acre Castlemartin stud in county Kildare – as he battled to stave off creditors' demands.

A rugby winger with caps for Ireland and the Lions, O'Reilly went on to a successful business career, rising to be chief executive and chairman of the giant US food group Heinz. But the 78-year-old's business interests have come crashing down around him.

Investments in the porcelain and crystal maker Waterford Wedgwood and newspaper group Independent News & Media (INM) resulted in huge losses. Lawyers for Allied Irish Banks said on Monday the bank had run out of patience with O'Reilly's efforts to repay €22m (£17.6m) of loans and a further €23m due from two of his investment companies. The court was told he had further debts of €195m. AIB accused the fallen tycoon of being insolvent and asked the courts to enter a judgment against him which would allow the bank to take control of key O'Reilly assets.

Michael Cush, counsel for O'Reilly, did not object, but asked for a six-month stay on the judgment so the tycoon is not forced into accepting fire-sale prices for his assets. Mr Justice Peter Kelly, presiding at the commercial court, said he would give his decision on whether to grant the stay on Friday.

O'Reilly has told AIB he intends repay money owed by selling assets, including a stake of about 5% in INM and Castlemartin, described as the "jewel in the crown" of his remaining properties. O'Reilly has even pledged to sell the church and graveyard on the estate, where his parents and two of his grandchildren are buried.

Michael Collins, counsel for AIB, told the court that the only reason O'Reilly had set out a sell-off plan was because of the bank's legal action, which was designed to get the businessman to "face up" to his obligations.

This was denied by Cush. O'Reilly told the bank last month he had sold investments worth more than $150m in the past three years, all of which had gone to repay borrowings. But AIB claimed only a fraction of that sum – $300,000 – went towards repaying its loans. Other creditors, who are owed about €195m, have agreed not to pull the plug to give O'Reilly more time to sell his assets in an orderly way.

Knighted in 2001, the imposing businessman was the saviour of Heinz and the owner of a stable of international newspapers. He mixed with an international circle of acquaintances, including politicians and scions of industry. After graduating from University College Dublin, he went on to head Ireland's dairy board in 1962, creating the Kerrygold brand and bringing marketing to Irish butter not seen before.

He left in 1966 to head the Irish Sugar Company but at the end of that decade was headhunted by Heinz to become the managing director of a UK subsidiary. He became chief executive, based in Pittsburgh, in 1979, and 12 years later was the first non-family member to become chairman. O'Reilly helped to transform the firm – its market value rose from $908m (£533m) to $11bn.

At the same time, he had been investing in Independent News & Media, the Irish media company that owns the Irish Independent and Sunday Independent. When he bought into the Dublin media company, it had a turnover of just €12m but under his ownership it grew into a worldwide company which at one point included the Independent in the UK as well as publications in Australia and South Africa. He stepped down as chief executive of the company on his 73rd birthday following a long battle with rival shareholder Denis O'Brien over the makeup of the board.

Earlier that year, he suffered another setback when the banks financing Waterford Wedgwood pulled the plug on the company and called in the receivers. O'Reilly and his brother-in-law Peter Goulandris had invested €400m over the previous five years.

With the status of an international business grandee, O'Reilly maintained the lifestyle to go with it, with homes in the Bahamas and the US as well as Ireland. His second wife is the Greek-American shipping heiress Chryss Goulandris, who was said to be wealthier than O'Reilly.