KLM ground staff are to go on strike at Schiphol next week after negotiations over pay and conditions broke down.

The CNV and FNV unions said they would call out their members for eight hours between 2pm and 10pm next Wednesday, after rejecting a pay offer from the airline last Friday.

A previous strike planned for last Saturday was blocked when a court ruled that it would be irresponsible to add to the pressure on the airport from weekend holiday traffic and the aftermath of last weekend’s Nato summit in The Hague.

KLM said it was considering legal action against next week’s strike, which coincides with the first week of the school holidays in the south of the country, but unions are confident they will be able to go ahead.

“Based on the passenger numbers we have obtained from Schiphol and the measures we have included in the safety protocol, we are convinced that this strike can take place safely,” CNV negotiator Souleiman Amallah said.

KLM said in May it wanted to freeze all staff wages for two yeas after its profits shrank last year by €271 million to €1.4 billion. CEO Marjan Rintel said in the annual report that there was a risk the airline “would not be able to keep investing in our future”.

Unions demanded a 7% pay increase and contrasted the pay freeze with the €2.2 million earmarked for executive bonuses, as well as the fact that pilots are being compensated for extra flexibility this summer season.

Jaap de Bie of the FNV’s aviation branch said the growing pay gap was unfair. “Ground staff are expected to work harder while seeing nothing in return,” he said.