The DUP and Alliance Party are neck and neck in second place among voters, according to a new opinion poll ahead of Thursday's Stormont election.
Sinn Fein remains on course to emerge as the largest party, according to the latest Institute of Irish Studies/University of Liverpool/Irish News poll.
The survey of voter intentions has Sinn Fein on 26.6%, slightly down from the previous University of Liverpool poll when it was on 27%.
Read More: Taoiseach Micheal Martin hopeful of UK-EU 'landing zones' after Stormont Assembly poll
However, broadly in line with other recent surveys, it retains a significant gap ahead of the DUP.
The latest poll of decided voters has Sir Jeffrey Donaldson's party on 18.2%, down from 20.2%.
If polling data is borne out at the May 5 Assembly election, Sinn Fein would displace the DUP as the region's largest party - a position it has occupied for almost 20 years - and it would be entitled to take the role of First Minister, with Michelle O'Neill the party's likely choice for the job.
However, there is uncertainty over whether a functioning Executive will be formed post-election.
The Executive collapsed in February when DUP First Minister Paul Givan quit in protest over Brexit's Northern Ireland Protocol and the barriers it has created on the movement of goods between Great Britain and the region.
The DUP has made clear it will not be returning to an Executive before major changes are secured to the contentious Irish Sea trading arrangements.
However, the poll has also indicated a surge in support for the cross-community Alliance Party, headed by Naomi Long, which has risen from 14.6% to 18.2%, level with the DUP.
The survey indicates that the Ulster Unionist Party has fallen back slightly to 12.1%, while the SDLP has seen a slight increase at 10.5%.
Other parties account for 14.4% of decided voters.
The poll indicates that 54% of voters for Jim Allister's TUV party plan to give the DUP their second preference, with 24% of DUP voters stating they will do the same for the TUV.
Almost two-thirds of DUP voters (62.8%) will instead give their second preference to the UUP.
More than half of Sinn Fein voters (52.2%) said they will transfer their second preference to the SDLP, but only 24.3% of SDLP voters said they will transfer immediately to Sinn Fein, with a higher number poised to give their second preference to the Alliance Party.
The Assembly election uses the single transferable vote system of proportional representation, which gives voters the opportunity to rank other parties in order of preference after selecting their first choice. - The poll was based on the responses of 1,270 people surveyed between April 16 and 26. It was conducted by Social Market Research Belfast and has a margin of error of plus or minus 3.1.
Get breaking news to your inbox by signing up to our newsletter