LONDON - The Swedish crown plummeted to a 17-year low on Thursday after the country's central bank delayed its next interest rate hike.

The Riksbank began normalising policy in December due to a strong economy but it has since joined its counterparts in Europe and Canada in adopting a cautious outlook.

Still, its message of restraint and concern about weak inflationary pressure caught some investors off guard.

The crown sank 1.4 percent versus the dollar to 9.55, its lowest since August 2002 and was headed for its biggest daily loss versus the euro since November.

"This extraordinary monetary policy stance continues to whack the crown and the Riksbank change in tone seems warranted," said Societe Generale analyst Kit Juckes.

The central bank said at its previous meeting that it planned to tighten policy in the second half of this year but Nordea Markets Analyst Torbjorn Isaksson said the bank was unlikely to hike until 2020 or possibly later.

Inflation in Sweden has lost steam despite getting a boost from a currency that has weakened steadily over the last six years.

The euro languished near a 22-month low, weighed down by ailing growth in Germany and the spectre of political uncertainty in Spain.

A surprise drop in German business morale has highlighted the divergence between economic data in the United States and the euro zone.

The euro has recently traded in a fairly narrow range but expectations of price swings in next month’s elections for the European Parliament have risen according to implied volatility gauges.

The European Central Bank in March pushed out the timing of its first post-crisis rate hike until 2020 and that is impacting the euro. It suffered its worst day in over six weeks on Wednesday, falling 0.6 percent to a 22-month low of $1.1141.

It traded flat on Thursday at $1.1154.

"Political uncertainties combined with economic concerns are a rather bad cocktail for the euro," Antje Praefcke, an analyst at Commerzbank, wrote in a note to clients.

A polarised election in Spain on Sunday could further dampen the euro's prospects.

The greenback rallied to a 23-month high of 98.189 against a basket of key rivals largely propelled by the euro's weakness. The index last traded 0.15 percent lower at 98.027.

Investors will watch the release on Friday of U.S. gross domestic product data for the first three months of 2019, for signs of whether the United States remains stronger than other leading economies.

(Reporting by Tom Finn Editing by Raissa Kasolowsky) ((tom.finn@tr.com; +44 2075427508 ; Reuters Messaging: tom.finn.reuters.com@reuters.net))