HSBC on Monday warned the coalition government that radical reform of the banking industry could put more UK jobs at risk as it confirmed 30,000 roles are to be lost across its global banking group over the next three years.

The new chief executive Stuart Gulliver, who took the helm in January after 32 years at the bank, revealed that 5,000 roles had already gone so far this year and that another 25,000 would need to be removed from the 296,000 global workforce.

Revealing the extent of the job cuts for the first time, Gulliver had signalled in May that roles would be shed as he set about achieving $3.5bn (£2.14bn) of savings within three years to bolster the bank's return on equity to 12%-15% from 9.5% in 2010. He stressed that some of the reductions would come through natural staff turnover and that the bank would continue to hire in some of its faster growing markets.

But the bank refused to be specific about how deeply the job axe would be wielded in the UK - where 700 roles were cut in June - and warned that no decision would be taken until the Independent Commission on Banking (ICB) published its recommendations on 12 September.

Gulliver said that the number of job cuts "did not take account of what the ICB might recommend" nor the impact of disposals of any businesses in the 20 countries - out of 87 where it has operations - where the retail business is earmarked for closure.

David Fleming, Unite national officer, said: "It is now necessary for the bank to confirm to its UK workforce how this news will impact on them. The employees being hit by these extensive cuts were in no way responsible for the banking crisis, yet it is these staff, many of whom are low paid, who are having to pay for the bank's recovery.

Several UK banks, including HSBC, have lobbied against proposals that they should "ringfence" their high street operations away from their investment banking arms.

HSBC's chairman, Douglas Flint, would not specify what action the bank might make in response to the ICB but kept up his challenge to worldwide regulatory changes because of the impact they might have already on fragile developed economies.

"The pace and quantum of regulatory reform continues to increase at the same time as the global economy appears to be losing momentum in its recovery," Flint said.

Profits beat forecasts

The pair, who took the helm of the bank at the start of the year after messy boardroom reshuffle, were speaking as the bank reported better than expected first-half pre-tax profits of $11.5bn, up 3%, with the fastest growth coming from Asia and Latin America. The shares were among the biggest gainers in the FTSE 100, rising 4% to 612p by midday as the market digested the figures which were published at 9.15am and set a better than expected tone for the rest of the London-listed banks which report this week.

Some $2.1bn of profits were made in Europe, although they were down 39%, with the majority now generated in Hong Kong – some $3bn – and the rest of Asia Pacific – $3.7bn – where profits are up 32%. The troubled North American business managed a 5% increase in profits to $606m, the smallest generator of profit, with the Middle East bringing in $747m and Latin America $1.1bn.

The investment banking operations suffered a 12% fall in revenue as markets dried up during the eurozone and US debt crisis, but Gulliver said they had held up more strongly than rivals.

Gulliver, who had announced in May after a day-long investor meeting that he had concluded that retail business in 39 out of 61 countries was "subscale", said: "I am pleased with these results, which mark a first step in the right direction on what will be a long journey."

The loan impairment and other credit risk provisions were down 30% on the same period last year, reaching $5.3bn. A provision of £65m was made against HSBC's holdings of Greek bonds but it has taken no fresh hits against its Irish or Portuguese debt.

The second interim dividend for 2011 is $0.09 per ordinary share – the equivalent of $1.6bn.