Caucus waters down detention motion

The Labor caucus has agreed to a watered-down motion critical of the handling of offshore detention of asylum seekers.

West Australian MP Melissa Parke sought caucus approval on Tuesday for a motion calling on the government to scrap detention on Nauru and Manus Island unless greater human rights standards could be met.

But after a lengthy debate the caucus agreed to an amended motion committing Labor in government to "ensure the conditions of offshore processing meet with human rights standards and negotiate with PNG and Nauru for independent oversight of these facilities and calls on the government to do the same".

The amended motion also changed the word "credible" - in relation to reports of rapes and assaults of asylum seekers - to "serious and concerning".

Four Labor MPs spoke in favour of the motion during the debate and three against.

But the original motion was amended by opposition immigration spokesman Richard Marles, supported by frontbencher Stephen Jones.

Ms Parke and another MP spoke against the amended motion.

The debate was described as respectful and passionate.