Malta has raised strong objections to new Frontex operational guidelines and may even pull out of participation in patrols by the EU border agency.

The guidelines say that if it is not possible to return migrants picked up by Frontex vessels to the country they left from, they must be sent to the country hosting the Frontex mission.

Malta has always insisted that migrants rescued on the high-seas should be taken to the nearest port.

The guidelines were drafted by the European Council and will be discussed by the European Parliament.

They provide that Frontex units will first try to return migrants to the country from where the boat carrying them departed. When this is not possible, the migrants should be taken to the country hosting the mission, rather than the nearest port of call, as stipulated by international maritime laws.

The guidelines do make an exception. In the event of people being ill on board the rescued vessel, when there are pregnant women on board or if the boat is deemed to be unseaworthy, the migrants may be taken to the nearest port of call.

In terms of the new guidelines, should Malta host a Frontex mission, as it has done in the past two years, it will have to take all the immigrants rescued, even if they were picked up outside its search and rescue region and closer to other countries.

"We will still continue to follow our international obligations to the letter as we've always done but we will not accept changes to these international obligations," a Malta government spokesman said.