"Climate change is without a doubt the most pressing problem," the king said in his annual speech opening parliament that is written by the prime minister and his cabinet.

"Climate change and rising sea levels are happening much faster and are more serious than previously thought," he said at a historic church in The Hague.

"It is clear that in the coming years extra effort will be needed to reach climate goals," Willem-Alexander said.

He referred to deadly floods in southern Limburg province in July which also hit Germany, saying it forced the government to "look at planned measures anew to see where it can be speeded up."

With about a third of the country below sea level, the Netherlands has long been prone to major floods.

The country remained one of Europe's largest per capita emitters of greenhouse gases and has budgeted almost seven billion euros for next year to make homes and businesses more sustainable.

The king also said the European Union as a bloc faced "strategic decisions in its relations with China and Russia, as well as the United States."

"Trans-Atlantic co-operation remains the cornerstone of Dutch security policy, but at the same time we will have to invest more in European security policy," he said.

The Netherlands is still being run by a caretaker cabinet following March elections, amid a lack of consensus among the largest parties, including that of outgoing Prime Minister Mark Rutte.

Despite the coronavirus crisis and a caretaker government "the Dutch economy remained strong, especially if you compare that to other countries," said Willem-Alexander.

The Dutch economy is predicted to grow by 3.5 percent next year.

Outgoing finance minister Wopke Hoekstra will present the government's budget for 2022 later on Tuesday.

The budget included 100 million euros to build more homes in an overcrowded Dutch market and around 500 million euros to fight organised crime.

"The shocking murder of Peter R. de Vries was a low point," the king said, referring to the Dutch crime reporter who was assassinated in broad daylight in Amsterdam in July.

Willem-Alexander's speech, his ninth since assuming the throne in April 2013, lacked the traditional pomp and ceremony for paliament's opening because of anti-coronavirus measures.