Labor's communications spokeswoman Michelle Rowland fears the temporary regulations will be made permanent without proper consultation.

"Labor will not consent to this cheap shot on the workers of Australia Post and this breach of trust with the community," she said on Wednesday.

"There was no consultation on these regulations before they were announced, and there was no opportunity to examine the merits and impacts of alternative approaches."

Under the coronavirus-inspired model, thousands of motorbike posties would switch to delivery vans or move into warehouses to cope with increased demand.

Priority letter services would be suspended, letter deliveries moved to every second day, and five days would be allowed for intrastate posting.

The postal union estimates one in four jobs could be axed under the delivery model.

"Labor considers the parcels boom is an opportunity to preserve and create jobs - not cut them," Ms Rowland said.

Labor will try to set up a Senate inquiry into the issues facing Australia Post.

Communications Minister Paul Fletcher said the changes would see posties move from a declining arm of the business to one that was seeing an explosion in demand.

"This is about is supporting Australia Post to best meet the needs of the community," Mr Fletcher told parliament on Wednesday.

He said the changes weren't permanent, pointing to the end date of June 2021.

Australian Associated Press