A walk out by quarantine staff has not delayed any flights at Sydney Airport, authorities say.

The workers, who screen arriving passengers for biosecurity hazards and other prohibited items, stopped work at airports across the nation on Friday for four hours beginning at 6:00 a.m.

A spokeswoman for the Department of Agriculture, Fisheries and Forestry (DAFF), which employs the quarantine staff, told AAP there had been no delays at Sydney.

A spokesman for Sydney Airport would not comment on the matter.

The strike follows similar two-hour stoppages at airports last week, which caused some minor delays for travellers.

The industrial action is being carried out by members of the Community and Public Sector Union (CPSU) over stalled pay talks with the DAFF.

Talks on Thursday aimed at resolving the dispute failed to reach an agreement.

The CPSU is demanding a 3.6 percent pay rise, in line with the consumer price index.

It says it has been offered a three per cent rise.

Other workers involved in the strikes include cargo inspectors and staff examining inbound international mail.