Defense Ministry spokesman Constantino Mendez said the Spanish warship Canarias was heading toward the tuna-fishing vessel and was expected to sight the fishing boat before the pirates could reach port in Somalia.
"The situation is calm. There are no strange movements on deck and the boat is on a more or less stable course," the defense chief of staff, Gen. Jaime Dominguez, said.
The boat, the Alakrana, was boarded by Somali pirates early Friday when it was working waters 800 miles away from the nearest navy escort, the government said in a statement.
The government has set up a team headed by Deputy Prime Minister Maria Teresa Fernandez de la Vega alongside representatives of the defense, foreign, interior and environment ministries to work toward the tuna fishing vessel's liberation.
The team met Saturday to decide a strategy and the defense ministry said all options for resolving the hijack were open.
Ship owners of the remaining 17 Spanish boats fishing in the area have sent instructions for them to move further off shore or return to port, the fishing organization Cepesca said.
Juan Fernando Lopez Aguilar, Spain's former justice minister and the current president of the European Union's civil liberties commission, said that Europe relies on a strong NATO presence to police waters off East Africa but still needs to find an effective way to deal with piracy.
It was the second attack on the Alakrana in less than a month, officials said. On Sept. 4, while trawling in waters off the Seychelles the captain was forced to take evasive action to dodge a pirate attack.
In April 2008, a Basque tuna boat was hijacked by pirates off Somalia's coast and held for six days until a reported $1.2 million ransom was paid. Another Spanish trawler escaped a hijacking attempt in September 2008.
Spanish ship owners have called on the government to station military personnel aboard fishing boats off East Africa, citing France as an example.
Christophe Prazuck, a French military spokesman, said that all costs for stationing armed soldiers on French boats were covered by ship owners and that protection has been available since mid-August to "about ten boats."
Spain's defense ministry says that under Spanish law it cannot post a military presence aboard ships but last month gave permission for companies to hire private security guards armed with high-velocity rifles.
The ministry had previously allowed security guards with pistols, but the measure was seen as insufficient against bandits sometimes armed with rocket-propelled grenades.
Associated Press writer Cecile Brisson in Paris contributed to this report.