Finnish telecom network equipment maker Nokia today plunged to a surprise quarterly loss due to a delay in booking 5G payments.

Nokia said today that the security dispute surrounding rival Huawei was creating near-term pressure to invest. 

Shares in the company fell 10% to their lowest level in six months as Nokia said it also expected pressure in the second half of the year. 

The company said a failure to book about €200m of net sales related to 5G in North America weighed on its results. It expects to recognise the amount during the full year. 

Nokia's networks business generated a loss of €254m during the quarter, compared with a gain of €46m the same time last year, as its own investments into 5G are yet to generate profits. 

"The slow start to 2019 and expected weak overall first half puts significant pressure on execution in the second half," the company said. 

Nokia counts Sweden's Ericsson and China's Huawei as its main rivals.

Some analysts say the Finnish company may benefit from challenges faced by the Chinese group after Washington alleged its equipment could be used by Beijing for spying – charges Huawei deny. 

"Some customers are reassessing their vendors in light of security concerns, creating near-term pressure to invest in order to secure long-term benefits," Nokia said in a statement.

Nokia, which signalled in January that it would have a particularly weak first quarter, made an operating loss (non-IFRS) of €59m compared to a profit of €239m during the first quarter of 2018. 

That compared with analysts' profit expectations ranging from €175m to €457m in a Reuters poll.

The telecom networks industry has faced slowing demand since 4G network sales peaked in the middle of the decade but a new cycle of network upgrades appears to be kicking in as demand for 5G technology increases. 

Nokia – which said it had won 36 commercial 5G deals so far – repeated its January forecasts for a "flattish" market in 2019, and for its 2019 earnings per share of €0.25-0.29, and 2020 earnings per share of €0.37-0.42. 

That contrasts with rival Ericsson which last week posted January-March quarter profit that beat forecasts due to strong growth in North America and cost cuts, spurring the Swedish firm to lift its outlook for the global telecom networks market.