The opposition leader says there's frustration over the information National received on the meth testing of houses.

But Simon Bridges is welcoming a new report that's lowered the standard of safe level of exposure to methamphetamine.

He says the previous standard was too high and meant people were not getting the housing they could have.

"There still seems to be some vagaries in the evidence, so more work needs to be done, but ultimately if it means more people in houses with a lower standard, that'd be a really good thing."