The Electoral Commission NSW projects 11,500 pre-poll votes will be cast in the city of Dubbo, 4300 at Mudgee and 1350 at Wellington.

Pre-polling in the city of Dubbo will take place at 34 Talbragar Street from March 16.

The number of voters in the electorate has grown since the 2013 redistribution of electoral boundaries that come into effect from polling day 2015.

Almost 49,000 people in the electorate were eligible to vote in the 2011 election.

The electorate ran from north to south, with Eumungerie, Narromine, Canowindra and Wongarbon at its extremities.

On March 28 the seat will officially run east to west, with Gulgong and Mudgee, Eumungerie, Trangie and Tomingley on its boundaries.

The new-look electorate has lost Parkes, Forbes, Canowindra and Peak Hill, and gained Trangie, Mudgee, Gulgong and Wellington.

While there are more voters in the new-look electorate, fewer polling booths will be operating on election day later this month.

Polling booths will fall from 36 to 25.

Dubbo and district residents will no longer be able to cast a vote at the West Dubbo Guides Hall, Dubbo Hospital and Wambangalang.

But the hospital will join the ranks of declared institutions where voting will occur between March 23 and 27.

In Dubbo they include aged care facilities along with Dubbo Private Hospital.

Polling booths in the Dubbo local government area on March 28 will operate from 8am to 6pm at Ballimore, Buninyong, Dubbo North, Dubbo South, Orana Heights and Wongarbon public schools.

They will also be hosted by the Delroy and South campuses of Dubbo College, Lourdes Hospital and Community Health Service, and the Wesley Centre.

On Tuesday morning the electoral commission website reported that the date of the issuing of writs by the governor was "unknown".

Authorised rolls will be closed at 6pm on the day of the issuing of the writs.

The website did not identify the date of so-called "Nomination Day".

At noon on that day the returning officer for the seat of Dubbo will name its candidates.

Ballet draws for the Legislative Assembly and the Legislative Council will follow at 2pm and 3pm, respectively.

Already campaigning for the seat are Deputy Premier and State Member for Dubbo Troy Grant, Labor's Stephen Lawrence, The Greens' Matt Parmeter and Independent Colin Hamilton.

The electoral commission has promised final results for the Legislative Assembly by April 8 and the Legislative Council by April 15.

NSW voters will go to the polls on March 28 to elect the state's 56th parliament.

Information on the state poll is available at www.votensw.info.

Voting options for Dubbo residents for the 2015 NSW election set down for March 28

o Pre-poll from March 16 at 34 Talbragar Street.

o Postal vote by registering before March 25 and receiving ballot papers that must be returned by April 1. For deliveries outside Australia, registration closes on March 23. Go to www.votensw.info for registration details.

o iVote up until 1pm on election day. Eligibility and registration details are at www.votensw.info.

o Absentee vote at Town Hall in Sydney or any other official polling booth in NSW.