Herbert Smith Freehills partners have voted to reject all four proposals for the firm's new unified remuneration system, potentially damaging plans to overhaul its rigid pre-merger structure.

Partners will now be presented with a final alternative option, including elements of the four original proposals, which they will vote on in the coming weeks.

The news comes as HSF begins its search for new leadership, with a number of candidates emerging in the race to replace current joint chief executives David Willis and Gavin Bell.

Following last year's merger, it was thought that the firm's remuneration would become closer aligned to legacy Freehills' flexible, more merit-based lockstep. But in a recent vote, each one of four restructured models was rejected by partners.

One of the options that was voted down is understood to have been a very similar model to Freehills' former structure, which involved a heavily modified lockstep running from 40 to 120 points.

HSF currently operates a pure eight-year lockstep for equity partners running from 43 to 100 points. It is understood that the new lockstep will run within a similar point bracket.

The final proposal that has been drafted up features a managed lockstep enabling partners to be held back or moved up at certain intervals. Gateways have been removed at the senior level of the lockstep. The difference between the top and bottom of the equity will also be increased, along with the firm's bonus pool for partners.

One HSF partner said: "The new system will ensure consistency across the firm. It's not about just adopting the Freehills system which is what people presumed would happen but you need to create a competitive environment. There are people who are against change- you need to be able to adapt in the current climate."

The new structure, if voted through, is expected to take effect from 1 May 2014. It will also include a 'balanced scorecard' which takes into account partners' financial performance and business development, as well as other factors, after the firm's management agreed to introduce a merit-based element to partners' pay last week.

The process of appointing a new leadership team at HSF is also now underway, with Willis and Bell set to retire from the firm in April 2014.

It is understood that global head of corporate Patrick Mitchell, London managing partner Ian Cox, managing partner EMEA Allen Hanen and global head of dispute resolution Sonya Leydecker have expressed an interest in the role.

The Herbert Smith Freehills Global Council – the firm's governance body – will decide whether the dual role will be replaced by a single CEO or whether it will continue to be undertaken jointly. The appointment process is expected to be completed by the end of the year.