A midnight email sent by a Liberal senator has helped delay a hearing into the Rudd government's plan to means test the private health insurance rebate.

The coalition has boycotted the Senate economics committee into Labor's plan to means test the 30 per cent private health insurance rebate for singles earning more than $75,000, and households taking home more than $150,000.

The committee can only proceed if a majority of the seven substantive members are in attendance.

But the coalition's three committee members Alan Eggleston, David Bushby and Barnaby Joyce failed to show up at the scheduled time of 8.30am (AEST).

The decision to reschedule was made one hour after a quorum was not reached.

Independent senator Nick Xenophon had media engagements in South Australia and was unable to make up the quorum with government committee members.

But a spokeswoman for committee chairwoman Annette Hurley said the hearing would resume with quorum if Senator Xenophon appeared at the rescheduled time of 1pm AEST by telephone link.

Opposition parliamentary secretary for health administration Mathias Cormann sent the committee secretariat an email shortly after midnight AEST indicating the coalition senators would not participate in the mini-Senate inquiry into the Fairer Private Health Insurance Incentives Bill 2009.

"There's no proper reason to rush this. The only reason they want to rush this is to avoid scrutiny," Senator Cormann told AAP from Perth.

"The government is going through a political exercise."

Department of Health and Treasury officials should be asked to appear after other witnesses so issues arising from the inquiry could be put to them for clarification.

Health Minister Nicola Roxon had misled the public by promising to keep the private health insurance rebate earlier this year, while pursuing plans to cut it, Senator Cormann said.