Mary Walz, one of 21 senior Barings executives dismissed following the scandal, will appear before the tribunal in east London claiming that the bank was in breach of contract for failing to pay the bonus.
ING, which rescued Barings after it crashed with losses of pounds 830m, paid out pounds 90m in staff bonuses but none of those sacked over the affair received a penny. Ms Walz, an American who joined Barings from Bankers Trust in 1992, is claiming the pounds 500,000 bonus for work she did in 1994 before the bank's collapse.
Ms Walz was head of equity financial products in London and, as such, one of Leeson's direct line managers with day-to-day responsibility for supervision of his activities.
In the Bank of England report into the Barings affair she was criticised for not checking closely enough on Leeson's trading.
The industrial tribunal has the power under the Wages Act to order an employer to pay the full amount claimed. Barings maintained she had no entitlement to the bonus.
The decision of Barings to pay bonuses - some of which derived from income generated from Leeson's activities in Singapore - prompted widespread criticism, but the bank said it would have provoked a staff exodus had the bonuses not been paid.
A number of other Barings executives sacked as a result of the scandal are challenging findings against them. The Securities and Futures Authority found five Barings executives guilty of failure to show due skill, care and diligence earlier this year. Four other former executives are challenging similar findings.