The consultation is being launched with a public meeting in Crawley today.
A second meeting will be held in Worthing on Tuesday, July 19.
The Crawley meeting is in the The Fire Service Training Centre, Northgate Avenue.
The Worthing one is in Worthing Library, Richmond Road, Worthing.
Both start at 7pm.
Throughout the consultation fire officers will attend county local committee meetings, open days and public events.
They will also hold specially arranged forums for partners, businesses, the voluntary sector and members of public.
Feedback can also be given online, by post or phone.
West Sussex County Council said a full merger could make savings of £3.8million.
There are no plans to close any fire stations.
The consultation will run until October 6.
Both authorities will make a final decision on the merger at separate meetings in December.
County fire officer Max Hood said: “The pressures on public spending mean all local authorities are working to find ways of providing essential services with reduced budgets.
“A merger would see a significant change in the management and support costs of the fire and rescue service in West Sussex.
“It could also mean we can protect fire stations and the other front line services that people need.
“We’re still waiting for details on the future funding from the government before the business case on a possible merger can be completed, but it’s also important to listen to the views of local people before a final decision is taken.
“I hope as many as possible will attend the meetings and public events to speak to fire officers, read the consultation document or seek information via the websites before giving us their feedback on the way forward.”
The business case and consultation document is available online at www.westsussex.gov.uk/fire
Copies of the consultation document are available in libraries, help points, and in reception areas of local authorities, and printed copies can be sent on request.
Anyone who would like more information can contact the consultation team via email at [email protected] write to: Fire Redesign Team, WSFRS HQ, Northgate, Chichester PO19 1BD, or call 01243 753706.
If approved by central government, a merger would take effect from April 1, 2013.