Spanish coastguards have rescued a boat carrying 229 Africans trying to reach the Canary Islands, the biggest group in a single boat ever intercepted off the islands' coastline, a government official said on today.

Coastguards found the 30-metre fishing boat yesterday evening around 100 km (60 miles) south of Gran Canaria and took the would-be immigrants to the port of Los Cristianos in Tenerife, arriving just after midnight local time.

All the Africans were men, including at least 20 children, a spokeswoman for Spain's 112 emergency line said.

"Such a large fishing boat could not have set off from the shore directly into the sea," Juan Antonio Corujo, from Spain's Red Cross told Spanish national radio.

"This boat must have been loaded from a pier or probably smaller boats took people to the boat once it was at sea."

Spain's Red Cross treated the boat's occupants in Tenerife and five were taken to health centres for treatment for dehydration and hypothermia.

Dozens of Africans have died in recent months trying to take advantage of calmer summer seas to make the journey to Spain's Canary Islands and mainland in search of jobs in Europe.

Tens of thousands have made it to Spanish shores in recent years, prompting Spain's Socialist government to toughen its line on illegal immigration. Many thousands more are believed to have drowned or died of thirst or exposure in the attempt.

According to data from Spain's interior ministry, between January and August, the number of illegal immigrants arriving by boat on Spain's coast fell 8 percent compared to a year earlier and was down 64 percent on 2006.