BERLIN (Reuters) -Porsche said it was fighting to restore production volumes and to re-prioritise spending after supply chain snags, slow EV demand and a sales slump in China weighed on results in the first half.

The luxury sportscar maker was hit harder than rivals by recent aluminium supply shortages in Europe because of its high percentage of pre-ordered cars, low volumes and detailed car specifications, CEO Oliver Blume said on a call with reporters.

The dent in sales could not be compensated within months, forcing Porsche to lower its forecast for profit margin over sales, CFO Lutz Meschke said.

Shares were up 0.8% in morning trading, having earlier gained as much as 2%, recouping some losses on Tuesday after it disclosed the impact of the shortage at a European aluminium supplier.

Slower EV demand in Europe and China's luxury segments had prompted the carmaker to refocus its budget, Meschke said.

The carmaker was broadly cutting costs to help it hit its longer-term 20% return on sales target, and expected new opportunities like its after-sales business to play a bigger role in future, he said.

LANGUISHING STOCK PRICE

Shares in Porsche, a Volkswagen AG subsidiary that listed on the stock market just under two years ago, have sunk 42% since last May as setbacks - from software problems to launch delays and weakening sales in China - have shaken investor confidence.

Asked if the European Union would likely go ahead with a planned phaseout of new CO2-emitting cars, Blume predicted the regulation would be loosened to allow for combustion-engine vehicles to be sold if driven on synthetic fuels.

Porsche said earlier this week that the transition to all-electric sales would take longer than previously forecast, echoing warnings from other carmaker executives in recent months that goals for a full transition to EVs were too ambitious.

This has raised pressure on Oliver Blume, whose double role as CEO of both Porsche AG and Volkswagen has already stoked concerns over whether one individual can lead two German blue-chip companies.

Porsche's operating profit fell by just over a fifth in the first half to 3.06 billion euros ($3.32 billion), it said on Wednesday, with sales down 4.8% to 19.46 billion euros.

Its operating return on sales was 15.7%, just above the reduced outlook for the year announced on Tuesday of 14-15%.

($1 = 0.9217 euros)